JP2007122083A - Transfer method, transfer device, image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer method, a transfer device, an image forming method and an image forming apparatus for stably preventing troubles, such as magnification errors, central blanking images and transfer deviations, regardless of the elapsed time. <P>SOLUTION: A transfer roller 10 is constituted to be opposed to a photoreceptor 1 so that the direction of the recessed part of fine recessed and projecting grinding teeth 101 having directivity in a prescribed direction, which is caused on the surface of the transfer roller 10 by grinding and inclined at a prescribed angle with respect to perpendicular direction, is a direction where foreign matters are less likely to infiltrate the recessed part, when transfer paper 8 moves relative to the transfer roller 10. More specifically, the direction of the recessed and projecting grinding teeth 101 is made the same as the direction of the relative movement of the transfer paper 8 with respect to the transfer roller 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transfer method and apparatus in an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and an image forming method and apparatus used in the image forming apparatus.

2. Description of the Related Art Conventionally, image forming apparatuses that perform transfer using a transfer member, for example, a transfer roller, are known.
In such an image forming apparatus, the driving force from the image carrier to the transfer roller is such that the surface movement speed of the transfer roller at the nip between the transfer roller and the image carrier is greater than the surface movement speed of the image carrier. There is known an apparatus capable of obtaining a good image with no transfer misalignment even if the sheet is subjected to an impact during image formation by having a transmission means for transmitting the image (Transfer No. 2686267). Publication).

  In addition, it has already been found that by providing a peripheral speed difference between the image carrier and a transfer member such as a transfer roller, an improvement can also be seen in the voids (blank images) at the time of transfer. Yes.

  By the way, a transfer roller as a transfer member is usually constituted by a metal shaft and an elastic body such as conductive foam polyurethane around the shaft. Since the nip between the image carrier and the transfer roller affects the transfer performance, the tolerance of the outer diameter of the transfer roller is strictly controlled, and the transfer roller is generally aimed at the outer diameter of the metal shaft. After bonding a larger elastic body, it is manufactured by a method of polishing to a standard value of the outer diameter with a grindstone or the like.

  As shown in FIG. 9, the surface of the transfer roller thus prepared is subjected to a polishing process, as shown in FIG. 9, with a minute uneven shape having a directivity in a predetermined direction inclined by a predetermined angle with respect to a direction perpendicular to the surface. It is known that this polishing eye 101 is generated.

  However, as shown in FIG. 10, the direction of the concavo-convex polishing marks 101 is opposite to the direction opposite to the transfer sheet that proceeds in the direction of arrow B in the figure as a recording material (hereinafter referred to as the forward direction). In this state, when the peripheral speed of the transfer roller whose surface moves in the direction of arrow D is rotated so as to be faster than the peripheral speed of, for example, the photoreceptor 1 as the image carrier whose surface moves in the direction of arrow C. In particular, it has been found that the transfer force of the transfer material changes with time, causing a problem that the magnification error of the image on the transfer paper increases, the occurrence of a hollow image, or a transfer shift occurs. did.

As a result of intensive studies on the cause of such problems, the present inventors have found the following.
Generally, the electrostatic attraction between the transfer paper and the photoconductor is strong, and the transfer paper moves together with the surface of the photoconductor. At this time, when the transfer roller is rotated so that the peripheral speed of the transfer roller is higher than the peripheral speed of the image bearing member, for example, the transfer paper that moves together with the surface of the photosensitive member is A state of relative movement in the direction opposite to the traveling direction is obtained. Then, when the direction of the polishing marks on the surface of the transfer roller is the forward direction as shown in FIG. 10 with respect to the moving direction of the transfer paper, the foreign matter near the facing portion between the transfer paper and the transfer roller is polished. It becomes easy to enter the concave part of the eye. Then, for example, foreign matters such as background-stained toner and paper dust on the photosensitive member enter, or foreign matters such as toner enter when a non-feed jam occurs.
Further, at this time, the direction of the polishing eye is opposite to the direction of relative movement of the transfer paper with respect to the transfer roller, and the transfer roller rubs the back surface of the transfer paper. As a result, the paper dust is more likely to be generated, and the paper dust easily enters the concave portion of the polishing eye.
In this way, when foreign matter enters the concave portion, the surface of the transfer roller changes, specifically, the frictional force against the transfer paper decreases, and the transfer paper conveyance force changes particularly with time. It will decline. The above-described problem is likely to occur due to the decrease in the transfer force of the transfer paper.

  Such a problem occurs not only when the surface movement speed of the transfer member is higher than the surface movement speed of the image carrier, but also a difference in surface movement speed between the transfer member and the image carrier. In some cases, it can happen.

  The present invention has been made in view of the above background, and the object of the present invention is to provide a transfer method capable of stably preventing the occurrence of problems such as magnification error, hollow image, and transfer deviation, regardless of time. To provide a transfer device, an image forming method, and an image forming apparatus.

To achieve the above object, a first aspect of the invention, the transfer member having a large number of irregularities having directivity in a predetermined direction inclined at a predetermined angle with respect to the direction perpendicular to the front surface to the surface The surface is moved endlessly, the surface moves so that a difference in surface movement speed occurs between the transfer member and the image bearing member that bears the image, and the transfer member is opposed to the image bearing member and the transfer member. the nip portion is formed between, and passed through a transfer material to the nip, the transfer method for transferring an image to the transfer material from said image bearing member, the orientation of the recesses of the irregularities, the transfer member of the transfer material The transfer member is opposed to the image carrier to form the nip portion so as to follow the relative movement direction, and the pressing force pressing the transfer member against the image carrier is 40 N or more. it is characterized in that.

According to a second aspect of the invention has a number of irregularities having directivity in a predetermined direction inclined at a predetermined angle with respect to the direction perpendicular to the front surface to the surface, the surface is moved and the image bearing the image A surface moving speed difference is formed between the image carrier and a transfer member that forms a nip portion between the image carrier and a transfer member by passing a transfer material through the nip portion and transferring the image from the image carrier to the transfer material. the transfer device having a transfer member drive transmission means for endlessly the surface of the transfer member so that occurs, the orientation of the recesses of the irregularities, and orientation to follow the direction of relative movement of the transfer member of the transfer material As described above, the transfer member is arranged , and the pressing force for pressing the transfer member against the image carrier is 40 N or more .

The invention of claim 3, moves the surface of the image carrier that carries an image, to the surface a number of irregularities having directivity in a predetermined direction inclined at a predetermined angle with respect to the direction perpendicular to the front surface The transfer member having the surface is moved endlessly so that a surface moving speed difference is generated between the surface of the image carrier and the image carrier and the transfer member are opposed to each other, and the image carrier and the transfer member are transferred to each other. In the image forming method for forming an image by forming a nip portion with a member, passing a transfer material through the nip portion, and transferring an image from the image carrier to the transfer material. orientation, such that the direction to follow the direction of relative movement of the transfer member of the transfer material, are opposed and the transfer member and the image bearing member with each other to form the nip portion, in the image bearing member that pressure for pressing the transfer member is not less than 40N It is an butterfly.

A fourth aspect of the present invention, an image bearing member for bearing an image, and the image carrier driving means for moving the surface of the image bearing member, to a predetermined direction inclined at a predetermined angle with respect to the direction perpendicular to the front surface of A transfer member having a plurality of concavo-convex shapes having directionality on the surface, forming a nip portion with the image carrier, and transferring an image from the image carrier to the transfer material by passing the transfer material through the nip portion And a transfer member drive transmission means for moving the transfer member surface endlessly so that a surface movement speed difference is generated between the image bearing member and the image carrier. The transfer member is arranged so as to follow the direction of relative movement of the material to the transfer member, and the pressing force for pressing the transfer member against the image carrier is 40 N or more. To do.

According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect , the transfer member drive transmission means is arranged so that the surface movement speed of the transfer member in the nip portion is larger than the surface movement speed of the image carrier. It is characterized by comprising.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect , the transfer member drive transmission means is configured to move the surface of the transfer member endlessly by transmitting the driving force of the image carrier. It is characterized by that.

According to a seventh aspect of the present invention, in the image forming apparatus according to the fourth, fifth or sixth aspect , a removing means for removing the foreign matter adhering to the surface of the transfer member is provided.

According to an eighth aspect of the present invention, in the image forming apparatus according to the fourth, fifth, sixth, or seventh aspect , a conveyance path for conveying the transfer material to the nip portion is curved.

A ninth aspect of the invention is the image forming apparatus of the fourth, fifth, sixth or seventh aspect , wherein the transfer member having a foamed elastic layer having an average cell diameter of 50 to 100 μm on the surface is used. It is what.

  The transfer method according to claim 1, the transfer device according to claim 2, the image forming method according to claim 3, and the image forming apparatus according to claims 4 to 9, comprising an image carrier whose surface moves and a transfer member which moves endlessly A difference in surface movement speed occurs between them. Then, the transfer material passes through the nip portion between the image carrier and the transfer member, and the image from the image carrier is transferred to the transfer material. This transfer material usually has a strong electrostatic attraction between the image carrier and moves together with the surface of the image carrier. For this reason, a speed difference is generated between the transfer material and the transfer member. That is, the transfer material moves relative to the transfer member. Then, the direction of the concave-convex concave portion on the surface of the transfer member is the direction in which the transfer material moves relative to the transfer member, and the transfer member faces the image carrier. During relative movement, entry of foreign matter into the concave and convex portions becomes difficult. This makes it difficult for changes in the characteristics of the transfer member surface over time due to entry of foreign matter into the recesses on the transfer member surface, specifically, changes in conveying force due to a decrease in frictional force.

  In addition, unlike the case in which the convex tip of the concavo-convex shape is directed against the relative movement of the transfer material relative to the transfer member, the convex tip is less likely to rub against the transfer material, and the generation of foreign matter caused by rubbing, Specifically, it is possible to suppress the generation of powder generated by scraping at least one of the transfer material and the transfer member due to rubbing.

In particular, in the image forming apparatus according to the fifth aspect , since the surface movement speed of the transfer member in the nip portion is higher than the surface movement speed of the image carrier, the image is scraped onto the transfer material from the image carrier. Can be made. As a result, it is possible to prevent the occurrence of so-called hollows in which only the peripheral part of the image is transferred and the central part is not transferred.
Further, in the case where the endless movement of the surface of the transfer member is performed by transmitting the driving force of the image carrier, the image carrier and the transfer member move on the surface while slipping. Thus, the slip acts as a force for moving the surface of the image carrier from the transfer member by friction, and at the same time, the means for transmitting the driving force of the image carrier acts as a force against the force. To do. As a result, the braking force resulting from the slip always acts from the means for transmitting to the image carrier, and even if a transfer material is caught in, for example, a fixing device during the transfer and an impact occurs, the image is caused by the impact. It is not affected by backlash or the like when driving force is transmitted from the driving means for driving the carrier to the image carrier.

In particular, in the image forming apparatus according to the sixth aspect , since the driving force of the image carrier is transmitted to move the surface of the transfer member endlessly, it is not necessary to separately provide a driving source for the transfer member.

In particular, in the image forming apparatus according to the seventh aspect , since the foreign matter adhering to the surface of the transfer member is removed by the removing means, the foreign matter becomes the concave and convex portions when the transfer material is moved relative to the transfer member. Intrusion can be prevented. As a result, the above-described change in conveying force is less likely to occur.

In particular, in the image forming apparatus according to the eighth aspect , in order to reduce the size of the apparatus and shorten the image forming time, the transfer material accommodating portion for accommodating the transfer material and the nip portion are arranged close to each other and the transfer is performed. Even when the transfer material discharge direction from the material accommodating portion and the transfer material entry direction to the nip portion do not coincide with each other, the transfer material is conveyed to the nip portion via the curved conveyance path. Therefore, the transfer material can be surely guided and entered into the nip portion.
Further, in order to prevent a transfer deviation that is likely to occur when the transfer material enters the nip portion in a curved state, the concave portion having the predetermined direction is formed even when the contact pressure of the transfer member in the nip portion is increased. By using the transfer member having the foreign matter, it is difficult for foreign matter to enter the concave portion.

In particular, in the image forming apparatus according to claim 9 , by using a transfer member having a foamed elastic layer having an average cell diameter of 50 to 100 μm on the surface, the depth of the cells exposed on the surface of the foamed elastic layer is reduced. Since it can be suppressed to a predetermined value or less, even if foreign matter once enters the cell, the foreign matter can be easily removed by electrostatic force or the like.

According to the first to ninth aspects of the invention, there is an excellent effect that it is possible to stably prevent the occurrence of problems such as a magnification error, a hollow image, and a transfer deviation regardless of time .

In particular , according to the invention of claim 5 , there is an excellent effect that it is possible to prevent the occurrence of image dropout and obtain a better image. When the transfer member is configured to move endlessly by transmitting the driving force of the image carrier, the transfer material is affected even if the transfer material is impacted during transfer. Therefore, there is an excellent effect that a good image without transfer deviation can be obtained.

In particular, according to the invention of claim 6 , there is an excellent effect that the configuration is simplified.

In particular, according to the invention of claim 7 , there is an excellent effect that the occurrence of the above-mentioned problem can be prevented more favorably.

In particular, according to the invention of claim 8 , the apparatus can be reduced in size and the image forming time can be shortened, and even when the contact pressure of the transfer member with respect to the image carrier is increased to prevent transfer displacement. There is an excellent effect that the foreign matter can be prevented from entering the concave portion of the transfer member and the above problem can be prevented.

In particular, according to the ninth aspect of the present invention, since the depth of the cell exposed on the surface of the transfer member is suppressed to a predetermined value or less, even if the foreign matter enters the cell once, the foreign matter is removed by electrostatic force or the like. There is an excellent effect that it can be easily removed from the recess.

Hereinafter, an embodiment in which the present invention is applied to a laser printer (hereinafter referred to as a printer) which is an image forming apparatus will be described.
FIG. 1 is a diagram illustrating a schematic configuration of the printer. This printer includes a process cartridge 100 that contains image forming means for forming an image on a transfer sheet, which is a recording material as a transfer material, by electrophotography. An illustrated process cartridge 100 includes an OPC photosensitive member (hereinafter referred to as a photosensitive member) 1 having a diameter of 30 mm as an image carrier, a charging roller 2 as a charging unit, a developing unit 3 as a developing unit, and a cleaning unit 4 as a cleaning unit. Etc. are integrated into the housing 5 in a compact manner.

  A latent image writing unit 6 for writing an electrostatic latent image on the photoreceptor 1 is provided on the side of the process cartridge 100. As this latent image writing unit 6, for example, an optical signal corresponding to image information read by a scanner or the like is emitted from a semiconductor laser, and the laser beam is scanned by a polygon mirror that is driven to rotate. A device for writing an optical signal 6a corresponding to color-separated image information on a photosensitive member through a converging lens and a mirror for correcting surface tilt of a polygon mirror disposed in the optical path, a mirror for deflecting laser light, or the like is used. be able to.

  Further, below the process cartridge 100, the transfer paper 8 serving as a transfer material stored in the paper feed cassette 7 is separated and fed one by one, and the paper is fed by the paper feed roller 9. After the transfer paper 8 is once waited in front of the photosensitive member 1, the leading edge of the image formed on the photosensitive member 1 and the leading edge of the transfer paper 8 are nipped between the photosensitive member 1 and the transfer roller 10. A registration roller 11 is provided for re-feeding the transfer paper 8 in synchronism with the rotation of the photosensitive member 1 at the timing of reaching the part almost simultaneously.

  Further, above the process cartridge 100, a fixing device having a fixing roller 14 and a press roller 15 each including a heater 13 rotatably arranged so as to be pressed against each other across the conveyance path 12 of the transfer paper 8. 16 is provided. In addition, on the downstream side of the fixing device 16 in the transfer paper conveyance direction, the transfer paper 8 that has passed through the nip between the fixing roller 14 and the press roller 15 is discharged on the upper side of the main body case 200 a of the printer 200. A paper discharge roller 18 for discharging the paper to the stacker unit 17 is provided.

  In the printer 200 having such a configuration, first, the photosensitive member 1 rotates at a linear speed of 80 mm / sec, and is uniformly charged by charges from the charging roller 2 during the rotation. Next, the latent image writing unit is driven based on image information read from the outside, whereby the image information is formed as an electrostatic latent image in the charging area (image forming area) of the photoreceptor 1. . The electrostatic latent image formed on the photosensitive member 1 is developed with a developer (toner) supplied to the photosensitive member 1 by the developing roller 31 of the developing unit 3 to become a visible image (toner image).

  On the other hand, while the toner image is being formed on the photosensitive member 1, the transfer paper 8 is pulled out from the paper supply cassette 7 by the paper supply roller 9, and the leading end of the transfer paper 8 is in the nip of the registration roller 11. The transfer paper 8 is put on standby in a state where it is in contact with the portion. The transfer paper 8 starts rotating with the registration roller 11 in synchronization with the rotation of the photosensitive member 1 at the timing when the leading end of the transfer paper 8 and the leading end of the toner image coincide with each other. The toner image on the photoconductor 1 is transferred to a transfer position formed at a nip with a transfer roller 10 as a transfer member that is pressed against the photoconductor 1. Then, the transfer paper 8 onto which the toner image has been transferred is fixed on the transfer paper 8 by the fixing roller 24 and the press roller 25 of the fixing device 16, and is discharged onto the stacker unit 17 by the paper discharge roller 18. Paper. In the meantime, the residual toner remaining on the photosensitive member 1 without being transferred onto the transfer paper 8 in the transfer process of the toner image onto the transfer paper 8 is transferred to the photosensitive member 1 by the cleaning blade 4a of the cleaning unit 4. It is removed from above and collected in the cleaning container 4b.

  Further, an open / close cover 201 that forms a side surface of the main body case 200a on the transfer path 12 side of the transfer paper 8 is attached to the main body case 200a of the printer 200 by a cover support shaft 202 so as to be freely opened and closed. In the opening / closing cover 201, the static elimination needle 22 is disposed together with the transfer roller 10.

  In addition, a manual feed unit 23 for manually feeding transfer paper is attached to the open / close cover 201 of the printer 200 according to the present embodiment by a cover support shaft 202 that is shared with the open / close cover 201. The transfer paper fed using the manual feed unit 23 is conveyed to the registration roller 11 by the rotation of the manual paper feed roller 24 provided on the printer main body side. Further, the manual feed unit 23 is configured to be stored in a manual feed unit storage portion 201c formed on the outer side of the opening / closing cover 201 when not in use. The manual feed unit 23 is not necessarily provided. If the manual feed unit 23 is not provided, the manual feed unit storage portion 201c of the opening / closing cover 201 is not necessary.

  FIG. 2 is an explanatory diagram of a driving mechanism for driving the photosensitive member 1 and the transfer roller 10 in this printer. Flange 1L, 1R is provided at both ends of the photoconductor 1 in the rotation axis direction. The flanges 1L and 1R are formed in a shape that allows transmission of driving force from other members or transmission of the driving force of the photosensitive member to other members, for example, a gear shape. In this printer, of the two flanges, the right flange (hereinafter referred to as the right flange) 1R in FIG. 2 receives a driving force from a main motor (not shown) as an image carrier driving means, and thereby the photosensitive member is exposed to light. The body 1 is driven to rotate.

  Further, in this printer, the transfer roller 10 is driven by a transfer member drive transmission means for rotating the transfer roller 10 by transmitting the driving force of the photoreceptor 1. Specifically, the transfer member drive transmission means includes a flange 1L on the left side in FIG. 2 (hereinafter referred to as a left flange) of the two flanges, and one end on the left side of the shaft portion 10a of the transfer roller 10 in the drawing. And a drive gear 10b provided to mesh with the flange 1L. The left flange 1L transmits a driving force to the driving gear 10b of the transfer roller 10 member, so that the transfer roller 10 is rotationally driven. The left flange 1L and the drive gear 10b are set so that the peripheral speed of the transfer roller 10 is larger than the peripheral speed of the photoconductor 1, so that the photoconductor 1 and the transfer roller 10 rotate while slipping. . The slip acts as a rotational force for rotating the photosensitive member 1 from the transfer roller 10 due to friction, and at the same time acts as a force against the rotational force on the transfer member drive transmission means. Specifically, the left flange 1L receives a rotational force in a direction opposite to the rotational force from the drive gear 10b. As a result, the braking force resulting from the slip is always applied to the photosensitive member 1 from the transfer member drive transmission means, and the transfer paper 8 is engaged with, for example, the fixing roller 14 and the pressure roller 15 of the fixing device 16 during the transfer. Even if an impact occurs due to being inserted, the impact is not affected by backlash or the like when the driving force is transmitted from the main motor that drives the photoreceptor 1 to the photoreceptor 1. Therefore, even if the transfer paper 8 is subjected to an impact during the transfer, the transfer is not affected and a good image without transfer deviation can be obtained.

  Further, since the peripheral speed of the transfer roller 10 is higher than the peripheral speed of the photoconductor 1, the toner image is scraped onto the transfer paper 8 from the photoconductor 1 at the nip portion between the photoconductor 1 and the transfer roller 10. Can do. As a result, it is possible to prevent the occurrence of so-called hollows in which only the peripheral part of the image is transferred and the central part is not transferred. Therefore, a better image can be obtained.

  Further, in the printer according to the present embodiment, the transfer roller 10 is driven using the driving force of the photosensitive member 1, so that it is not necessary to separately provide a drive source such as a motor for driving the transfer roller 10. Configuration is simplified.

  In the printer according to the present embodiment, the transfer roller 10 has an elastic body layer provided on a metal shaft portion 10a, and the elastic body layer is polished to have a predetermined diameter (for example, a diameter of 16 mm). is there. As a material of the elastic layer of the transfer roller 10, conductive foamed polyurethane can be used. The average cell diameter of the cells of this elastic layer is preferably 50 to 100 μm. Within this range, the depth of the recess formed in the cell on the surface of the transfer roller 10 can be suppressed to a predetermined level or less, so that cleaning for removing foreign matter such as toner and paper dust in the cell is easy. Can be done. As a result, the cleaning property becomes good and the transfer property by the transfer roller 10 can be kept good. For example, when a cleaning method is employed in which a cleaning bias voltage is applied to the transfer roller 10 to move foreign matter such as toner or paper dust that has entered the inside of the cell to the photosensitive member 1 side, the foreign matter is transferred to the photosensitive member 1 side. The transfer roller 10 is easy to clean.

  The transfer roller 10 is pressed against the photosensitive member 1 by a pressing spring 20 from the printer main body side. In order to keep the nip between the transfer roller 10 and the photoreceptor 1 in a state where the transfer roller 10 is pressed against the photoreceptor 1 by the pressing spring 20, gap rollers 21 are provided at both ends of the transfer roller 10. Install and manage the nip.

  On the surface of the transfer roller 10, as described above, the fine uneven polishing marks 101 having a directivity in a predetermined direction inclined by a predetermined angle with respect to a direction perpendicular to the surface are generated by polishing. . When foreign matter such as toner or paper dust enters the recesses of the polishing eyes 101, the characteristics of the surface of the transfer roller 10 change. Specifically, there is a problem that the frictional force is reduced and the conveying force is reduced, the magnification error of the image on the transfer paper becomes large, the occurrence of a hollow image, or the transfer deviation occurs. Will be.

Furthermore, due to the following characteristics of the transfer roller 10 and the printer in the present embodiment, foreign matters such as toner and paper dust tend to affect the transfer roller 10.
In the printer of this embodiment, as shown in FIG. 1, in order to reduce the size of the apparatus and shorten the first print time, the conveyance path of the transfer paper 8 is shortened and curved. In both transport paths of the paper feed cassette 7 and the manual paper feed unit 23, the transfer paper 8 reaches the transfer nip portion (transfer position) with its leading end curved to the transfer roller 10 side. For this reason, the front end portion of the transfer paper 8 presses the surface of the transfer roller 10 relatively strongly. Therefore, in this printer, the pressing force of the pressing spring 20 is increased in order to oppose the pressure of the transfer paper 8 to the transfer roller 10 and press the transfer roller 10 toward the photosensitive member 1 side. As a result, the contact pressure between the transfer paper 8 and the transfer roller 10 becomes strong, the transfer roller 10 rubs the transfer paper 8, and foreign matters such as toner and paper dust tend to accumulate in the transfer nip portion (transfer position).
Table 1 shows the experimental results of examining the relationship between the transfer pressure (N) of the pressing spring 20 to the transfer roller 10 and the occurrence of “transfer deviation”. When the transfer pressure was 16 N, “transfer misalignment” occurred only when the transfer paper was fed from the manual paper feed unit 23. When the transfer pressure was 24 N, “transfer misalignment” occurred only when the thick transfer paper was fed from the manual paper feed unit 23. When the transfer pressure was 32 N, “transfer misalignment” occurred only at the trailing edge of the thick transfer paper fed from the manual paper feed unit 23. When the transfer pressure was 40 N and 48 N, no “transfer misalignment” occurred for all transfer sheets used in the printer. Based on the above results, in the printer of the present embodiment, the transfer pressure of the pressing spring 20 against the transfer roller 10 is set to 48 N in consideration of other apparatus conditions.

  In an image forming apparatus such as a printer according to the present embodiment, the use of recycled paper is increasing due to increasing interest in the user's environment. Since the fiber of the recycled paper is fine, the transfer nip portion (transfer position) paper dust tends to accumulate as compared with plain paper.

  Therefore, in the present embodiment, the transfer roller is configured such that the direction of the concave portion of the polishing eye 101 is such that foreign matter does not easily enter the concave portion when the transfer paper 8 moves relative to the transfer roller 10. A configuration in which 10 is opposed to the photoreceptor 1 is employed. Specifically, as shown in FIG. 3, the direction of the concavo-convex polishing eyes 101 is made to follow the direction of relative movement of the transfer paper 8 with respect to the transfer roller 10. This configuration operation will be described in detail below.

  In the illustrated apparatus, the photoconductor 1 rotates in the direction of arrow C. Further, the transfer roller 10 rotates in the direction of the arrow D, and the peripheral speed of the transfer roller 10 is set larger than the peripheral speed of the photosensitive member 1 as described above. As described above, the transfer paper 8 moves together with the photosensitive member 1 by the electrostatic attractive force from the photosensitive member 1. That is, the transfer paper 8 advances in the direction of arrow B as the photoconductor 1 rotates. The transfer paper 8 has a speed substantially equal to the peripheral speed of the photoconductor 1 or a speed slightly closer to the peripheral speed of the transfer roller than the peripheral speed of the photoconductor 1 due to the movement of the surface of the transfer roller 10, that is, the photoconductor. It moves at a speed slightly faster than the peripheral speed of 1. Accordingly, the transfer paper 8 moves relative to the transfer roller 10 in the direction opposite to the arrow B direction. In the apparatus according to the present embodiment, the transfer roller 10 is disposed so as to prevent foreign matter from entering the concave portion during the relative movement. Specifically, the transfer roller 10 is made to face the photoconductor 1 so that the concavo-convex polishing eyes 101 do not oppose, so that the polishing eyes are oriented in the direction of the relative movement. This makes it difficult for foreign matter to enter the concave portion, and changes in characteristics of the surface of the transfer roller 10 over time due to foreign matter entering the concave portion, for example, changes in conveying force due to a decrease in frictional force are less likely to occur. Therefore, it is possible to stably prevent the occurrence of problems such as magnification error, hollow image, and transfer misalignment regardless of time.

  Further, in the printer according to the present embodiment, the convex tip of the polishing eye 101 is in a direction that follows the direction of relative movement of the transfer paper 8 with respect to the transfer roller 10, so that the convex part opposes the relative movement. Unlike the case of the orientation, the convex portion is less likely to rub against the transfer paper 8, and the generation of paper dust caused by the rub can be suppressed. Therefore, since it can prevent that this paper dust generate | occur | produces and it enters into the said recessed part, generation | occurrence | production of the said problem by the entrance of the foreign material to this recessed part can be prevented more favorably.

Further, in the printer according to the present embodiment, it is desirable to provide a removing means for removing foreign matters such as toner and paper dust adhering to the surface of the transfer roller 10. For example, as shown in FIG. 4, a removing member 30 such as a mylar may be provided in contact with the surface of the transfer roller 10. Thereby, it is possible to better prevent the foreign matter adhering to the surface of the transfer roller 10 from entering the concave portion of the polishing eye 101 at the nip.
It should be noted that other configurations may be employed as the removing means. For example, as shown in FIG. 5, if a removing member 30 such as a mylar is combined with a brush roller 31, it is possible to satisfactorily remove foreign matter that has entered the recesses of the polishing eyes 101. In particular, in the case of this configuration, the tip of the brush roller 31 can be inserted into the concave portion of the polishing eye 101, and the foreign matter that has entered the concave portion can be removed by scraping.
By providing the removing means exemplified in FIGS. 4 and 5 above, it is possible to more satisfactorily prevent the occurrence of problems such as the magnification error, hollow image, and transfer deviation.

  Hereinafter, more specific examples of the present invention will be described.

[Example 1]
In the apparatus shown in FIG. 1, the direction of the concavo-convex polishing marks of the transfer roller 10 is rotated so as to follow the direction of relative movement of the transfer paper to the transfer roller 10 as shown in FIG. Were continuously printed, and changes in the coefficient of friction, the rank of occurrence of a hollow image, and the magnification error with respect to the number of sheets passed were observed. The results at this time are shown by white circles in FIG. 6, FIG. 7, and FIG. Note that the standard value of the friction coefficient in this apparatus is 1.0 or more. Further, the larger the numerical value of the blank image generation rank, the smaller the number of blank images generated, and the blank rank 5 indicates that no blank image is generated. In this apparatus, a rank of 4 or higher is allowed, and when the rank is 3.5 or lower, it is treated as an abnormal image. The magnification error indicates the expansion / contraction of the image length in the paper traveling direction with respect to the theoretical value. When the image length in the traveling direction of the transfer paper is L2, and the theoretical value of the image length is L1, It is expressed by a formula.

  In this apparatus, this magnification error is a guaranteed value up to 1%.

[Comparative Example 1]
The continuous printing is performed in the same manner as in Example 1 except that the polishing eye of the transfer roller 10 of Example 1 is rotated in the direction opposite to the direction of relative movement of the transfer paper to the transfer roller 10 as shown in FIG. It was. The results are shown by black circles in FIGS. 6, 7 and 8.

  As can be seen from FIGS. 6, 7, and 8, in Comparative Example 1, when the 50,000 sheets were passed, the hollow image rank was 3.5, and a hollow image was generated. Further, when 125,000 sheets were passed, the rank was lowered to 2, and the occurrence of a hollow image became remarkable. The magnification error of the image was 1% after passing 25,000 sheets, and the magnification error was 1.3% at the time of passing 50,000 sheets, which was out of the guaranteed value. Thus, in order to investigate the cause of the occurrence of a hollow image or the enlargement of the magnification error, the component analysis of the surface of the transfer roller 10 was performed when 50,000 sheets were passed. The components calcium carbonate, talc and toner components were detected. It was also found that the coefficient of friction of the surface decreased to 0.83 after passing 50,000 sheets (A4 size, landscape passing) with respect to the initial 1.5.

On the other hand, in Example 1, up to 200,000 sheets, the blank image rank 4 or higher was maintained, and the magnification error of the image was kept at a small value within 1%. In addition, component analysis on the surface of the transfer roller 10 after passing 50,000 sheets (A4 size, landscape paper) was carried out, and talc, calcium carbonate, and toner components as paper components were detected on the surface of the transfer roller 10. However, the absolute amount of talc and calcium carbonate was about 1/3 that of Comparative Example 1, and the toner component was about 1/2. The surface friction coefficient is 1.5 after initial passing of 50,000 sheets (A4 size, landscape paper), and maintains a sufficient friction coefficient even after passing 50,000 sheets. It was.

  As described above, the friction coefficient of the transfer member is reduced by rotating the concave and convex polishing eyes of the transfer roller 10 in the reverse direction opposite to the direction against the relative movement of the transfer paper 8 with respect to the transfer roller 10. While an abnormal image is generated, good image quality can be maintained by rotating in the forward direction until the component life is reached after passing 60,000 to 80,000 sheets. The numbers shown in this embodiment are specific to the apparatus of the embodiment and change depending on the photosensitive member linear velocity, the transfer member material, and the like.

In the embodiment described above, the transfer has rollers only described the example of applying the present invention to a device using a predetermined inclined at a predetermined angle with respect to the direction perpendicular to occur and the surface in the manufacturing process as a transfer member The image carrier is moved by endlessly moving the surface of the transfer member having a large number of concave and convex shapes on the surface, and the transfer member faces the image carrier carrying the image. A transfer method, a transfer device, and an image forming method using the transfer method, wherein a nip is formed between the transfer member and the transfer member, a transfer material is passed through the nip, and an image is transferred from the image carrier to the transfer material. The present invention can be applied to any image forming apparatus. For example, the present invention can be applied when a transfer belt is used as the transfer member.

1 is a front view illustrating a schematic configuration of a laser printer according to an embodiment. FIG. 3 is an explanatory diagram of a driving mechanism that drives a photoconductor and a transfer roller 10 in the printer. FIG. 3 is an explanatory diagram of a facing portion between the photosensitive member and the transfer roller 10 in the printer. FIG. 3 is an explanatory diagram showing a configuration example of a removing unit that removes the surface of the transfer roller 10. Explanatory drawing which shows the other structural example of the removal means. Explanatory drawing which shows the change of the friction coefficient with respect to the number of paper passing. Explanatory drawing which shows the change of a hollow-out image generation rank with respect to the number of paper passing. Explanatory drawing which shows the change of the magnification error with respect to the number of passing sheets. FIG. 3 is an explanatory diagram of a polishing eye 101 on the surface of the transfer roller 10. Explanatory drawing of the opposing part of the photoreceptor 1 and the transfer roller 10 in the conventional apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 3 Developing unit 4 Cleaning unit 5 Housing 6 Optical signal 8 Transfer paper 10 Transfer roller 11 Registration roller pair 14 Fixing roller 15 Pressure roller 16 Fixing device 20 Pressing spring 21 Gap roller 30 Removal member 31 Brush roller

Claims (28)

Endlessly moving the surface of the transfer member having a plurality of concave and convex shapes on the surface that are generated during the manufacturing process and having a directivity in a predetermined direction inclined by a predetermined angle with respect to a direction perpendicular to the surface; The transfer member is opposed to an image carrier that carries an image so that a surface movement speed difference occurs between the image carrier and an image carrier, and a nip portion is formed between the image carrier and the transfer member. In a transfer method in which a transfer material is passed through a portion and an image is transferred from the image carrier to the transfer material,
The transfer member is opposed to the image carrier so that the foreign material does not easily enter the recess during the relative movement of the transfer material to the transfer member. A transfer method comprising forming a portion. The transfer method according to claim 1.
The transfer method, wherein the predetermined direction is a direction in which a convex tip follows the direction of the relative movement. The transfer method according to claim 1 or 2,
A transfer method characterized in that the surface of the transfer member is moved endlessly so that the surface movement speed of the transfer member in the nip portion is larger than the surface movement speed of the image carrier. The transfer method according to claim 1, 2 or 3,
A transfer method, wherein the driving force of the image carrier is transmitted to move the surface of the transfer member endlessly. In the transfer method according to claim 1, 2, 3 or 4,
A transfer method comprising removing foreign matter adhering to the surface of the transfer member. The transfer method according to claim 1.
A transfer method, wherein the transfer material is conveyed to the nip portion via a curved conveyance path. The transfer method according to claim 1.
The transfer method, wherein the transfer member has a foamed elastic layer having an average cell diameter of 50 to 100 μm on the surface. An image carrier that has a large number of concave and convex shapes on the surface that occur during the manufacturing process and that is inclined at a predetermined angle with respect to a direction perpendicular to the surface, the surface moves, and carries an image A transfer member that forms a nip portion between the image bearing member and the transfer member by passing a transfer material through the nip portion,
In a transfer apparatus having transfer member drive transmission means for endlessly moving the surface of the transfer member so that a surface movement speed difference occurs between the image carrier and the image carrier,
A transfer apparatus in which the transfer member is disposed so that the direction of the recess having the concavo-convex shape is less likely to cause entry of foreign matter into the recess during relative movement of the transfer material to the transfer member. . The transfer device according to claim 8.
The transfer apparatus, wherein the predetermined direction is a direction in which a convex tip follows the direction of the relative movement. The transfer device according to claim 8 or 9,
A transfer apparatus, wherein the transfer member drive transmission means is configured such that the surface movement speed of the transfer member in the nip portion is greater than the surface movement speed of the image carrier. The transfer device according to claim 8, 9 or 10,
A transfer apparatus comprising the transfer member drive transmission means configured to move the surface of the transfer member endlessly by transmitting a driving force of the image carrier. The transfer device according to claim 8, 9, 10 or 11,
A transfer apparatus comprising a removing means for removing foreign matter adhering to the surface of the transfer member. The transfer device according to claim 8.
A transfer apparatus, wherein a transfer path for transferring the transfer material to the nip portion is curved. The transfer device according to claim 8.
The transfer member has a foamed elastic layer having an average cell diameter of 50 to 100 μm on the surface thereof. Transfer having the surface of an image carrier carrying an image and having a large number of concave and convex shapes on the surface having a directivity in a predetermined direction inclined by a predetermined angle with respect to a direction perpendicular to the surface and generated during the manufacturing process The surface of the member is moved endlessly so that a surface moving speed difference is generated between the surface of the image carrier and the image carrier and the transfer member are opposed to each other. In the image forming method of forming an image by forming a nip portion between, transferring a transfer material through the nip portion, and transferring an image from the image carrier to the transfer material.
The transfer member and the image carrier are opposed to each other so that the direction of the concave-convex concave portion is such that foreign matter does not easily enter the concave portion when the transfer material moves relative to the transfer member. An image forming method comprising forming the nip portion. The image forming method according to claim 15.
The image forming method according to claim 1, wherein the predetermined direction is a direction in which a convex tip follows the direction of the relative movement. The image forming method according to claim 15 or 16,
An image forming method, wherein the surface of the transfer member is moved endlessly so that the surface movement speed of the transfer member in the nip portion is larger than the surface movement speed of the image carrier. The image forming method according to claim 15, 16 or 17.
An image forming method, wherein the surface of the transfer member is moved endlessly by transmitting a driving force of the image carrier. The image forming method according to claim 15, 16, 17, or 18.
An image forming method comprising removing foreign matter adhering to the surface of the transfer member. The image forming method according to claim 15.
An image forming method, wherein the transfer material is conveyed to the nip portion via a curved conveyance path. The image forming method according to claim 15.
The transfer member has an elastic foam layer having an average cell diameter of 50 to 100 μm on the surface thereof. An image carrier for carrying an image;
Image carrier driving means for moving the surface of the image carrier;
A plurality of concavo-convex shapes generated in the manufacturing process and having a directivity in a predetermined direction inclined at a predetermined angle with respect to a direction perpendicular to the surface, forming the image carrier and the nip portion, A transfer member that passes the transfer material through the nip portion and transfers the image from the image carrier to the transfer material;
In an image forming apparatus having transfer member drive transmission means for moving the transfer member surface endlessly so that a surface movement speed difference occurs between the image carrier and the image carrier.
The transfer member is arranged so that the direction of the concave portion having the concavo-convex shape is such that foreign matter does not easily enter the concave portion when the transfer material moves relative to the transfer member. Image forming apparatus. The image forming apparatus according to claim 22, wherein
The image forming apparatus according to claim 1, wherein the predetermined direction is a direction in which a convex tip follows the direction of the relative movement. The image forming apparatus according to claim 22 or 23.
An image forming apparatus, wherein the transfer member drive transmission means is configured such that a surface movement speed of the transfer member in the nip portion is larger than a surface movement speed of the image carrier. The image forming apparatus according to claim 22, 23, or 24.
An image forming apparatus, wherein the transfer member drive transmission means is configured to endlessly move the surface of the transfer member by transmitting a driving force of the image carrier. The image forming apparatus according to claim 22, 23, 24, or 25.
An image forming apparatus comprising a removing unit for removing foreign matter adhering to the surface of the transfer member. The image forming apparatus according to claim 22, wherein
An image forming apparatus, wherein a conveyance path for conveying the transfer material to the nip portion is curved. The image forming apparatus according to claim 22, wherein
An image forming apparatus using the transfer member having a foamed elastic layer having an average cell diameter of 50 to 100 μm on the surface.

Images