JP3910127B2 - Simultaneous double-sided image forming device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus that forms an image on a recording medium such as a sheet or an OHP film, such as a printing machine, a copying machine, a printer, a facsimile machine, or a complex machine thereof.
[0002]
[Prior art]
In recent years, some image forming apparatuses of this type form images on both sides of a recording medium.
[0003]
As such an image forming apparatus, for example, there is an apparatus including a reversing device that reverses a recording medium.
[0004]
In this image forming apparatus, when forming an image on both sides of the recording medium, the recording medium on which the image is formed on the front surface is reversed by putting it in the reversing device, and this time, an image is formed on the back surface of the recording medium and discharged. Was.
[0005]
[Patent Document 1]
JP 2000-352889 A
Patent Document 1 describes a technique of an image forming apparatus provided with two image forming apparatuses in a housing.
[0006]
In this image forming apparatus, when images are formed on both sides of a recording medium, one image forming apparatus forms an image on the surface of the recording medium, and the other image forming apparatus forms an image on the back surface of the recording medium. As a result, images were simultaneously formed and discharged on both the front and back sides of the recording medium.
[0007]
However, the image forming apparatus having the former reversing device forms an image on the front surface of the recording medium after forming the image on the front surface of the recording medium and then inverting the recording medium in the reversing device and then forming the image on the back surface. However, it takes time to form an image.
[0008]
Further, since the latter image forming apparatus includes two image forming apparatuses in the housing, there are problems that the size of the image forming apparatus is increased and the image forming apparatus is expensive.
[0009]
In order to solve these problems, for example, as shown in FIG. 9, the image forming carrier 12, the primary image carrier 20, the primary transfer means 25, the secondary image carrier 30, the secondary cleaning means 35, the secondary cleaning means 35 shown in FIG. There is a simultaneous double-sided image forming apparatus including a transfer unit 36 and the like.
[0010]
In this simultaneous double-sided image forming apparatus, when images are formed on both the front and back sides of the recording medium P, first, a toner image for each color is formed on each image forming carrier 12, and the toner image for each color is carried as a primary image. After the first full color image is formed by transferring to the body 20, the first full color image on the primary image carrier is transferred to the secondary image carrier 30 by the primary transfer means 25, and the secondary image carrier is obtained. 30 holds the first full-color image.
[0011]
Next, after the image forming carrier 12 and the primary image carrier 20 are cleaned, a color-specific toner image is separately formed on each image-forming carrier 12, and the color-specific toner image is transferred to the primary image carrier. 20 to form a second full-color image, and the primary image carrier 20 holds the second full-color image.
[0012]
Next, the recording medium P is conveyed in time with the first full-color image and the second full-color image described above, and the second full-color image on the primary image carrier 20 is transferred to the recording medium P by the primary transfer unit 25. While transferring to the front surface, the first full-color image on the secondary image carrier 30 was transferred to the back surface of the recording medium P by the secondary transfer means 36.
[0013]
Finally, the transfer residual toner on the primary image carrier 20 and the secondary image carrier 30 is cleaned by the respective cleaning means to prepare for the next transfer.
[0014]
By the way, the secondary cleaning means 35 provided in the secondary image carrier 30 of the simultaneous double-sided image forming apparatus includes, for example, a brush roller 59A, a bias roller 59B, a cleaning blade 59C, and the like.
[0015]
When cleaning is performed, the bias roller 59B is charged by a voltage application unit (not shown) by rotating around the support shaft 56 in the direction of the arrow c, thereby charging the brush roller 59A and carrying the secondary image. The transfer residual toner on the body 30 is electrically adsorbed and cleaned, and the tip of the hair of the brush roller 59A is pressed against the secondary image carrier 30 to scrape the surface and physically clean the transfer residual toner. It was in a cleaning state to remove.
[0016]
[Problems to be solved by the invention]
However, the transfer residual toner on the secondary image carrier 30 after being transferred to the back surface of the recording medium P is after the transfer has been performed three times, and the charge distribution of the transfer residual toner becomes wide. No. 35 has a problem that it cannot be removed cleanly.
[0017]
Further, the secondary image carrier 30 using a specific material changes depending on the environment such as the installation location of the simultaneous double-sided image forming apparatus, so that the surface resistance, the separation resistance, the volume resistance, and the like change. There was a problem that could not be removed cleanly.
[0018]
Therefore, a first object of the present invention is to transfer the first image carried on the primary image carrier described above to the secondary image carrier by the primary transfer means, and then separately transfer the first image onto the primary image carrier. In a simultaneous double-sided image forming apparatus that forms two images on both sides of a recording medium by carrying two images, transferring the second image by a primary transfer unit, and transferring the first image by a secondary transfer unit, respectively. The purpose is to improve image formation by neatly removing the transfer residual toner on the carrier.
[0019]
The second object of the present invention is to facilitate handling of the release agent.
[0020]
A third object of the present invention is to provide an inexpensive simultaneous double-sided image forming apparatus.
[0021]
A fourth object of the present invention is to further improve image formation by further removing the transfer residual toner on the secondary image carrier.
[0022]
A fifth object of the present invention is to further improve image formation by reducing the influence on the first image on the secondary image carrier.
[0023]
A sixth object of the present invention is to collect residual transfer toner and reuse resources.
[0024]
A seventh object of the present invention is to further improve image formation by improving the transfer performance from a secondary image carrier to a recording medium.
[0025]
An eighth object of the present invention is to obtain a high-definition image.
[0026]
  Therefore, the invention according to claim 1 is to achieve the above first, fourth, and fifth objects.
  After the first image carried on the primary image carrier is transferred to the secondary image carrier by the primary transfer means, a second image is separately carried on the primary image carrier, and the second image is primary transferred. In the simultaneous double-sided image forming apparatus for forming the images on both sides of the recording medium by respectively transferring the first image by the secondary transfer means,
  Secondary cleaning means for removing transfer residual toner on the secondary image carrier,Arranged downstream of the transfer position by the primary transfer means and the transfer position by the secondary transfer means in the rotational conveyance direction of the secondary image carrier,Application member for applying release agent for easy removal of transfer residual toner to application position on secondary image carrierAnd a cleaning member disposed further downstream of the coating member and provided so as to be able to contact and separate from the secondary image carrier.With,
  in frontWhen applying the release agent, after the application member is in contact with the secondary image carrier, the cleaning member is in contact,
  When the release agent is not applied, the application member is separated from the secondary image carrier.
[0027]
  The invention according to claim 2 is to achieve the above first, fourth, and fifth objects.
  After the first image carried on the primary image carrier is transferred to the secondary image carrier by the primary transfer means, a second image is separately carried on the primary image carrier, and the second image is primary transferred. In the simultaneous double-sided image forming apparatus for forming the images on both sides of the recording medium by respectively transferring the first image by the secondary transfer means,
  Secondary cleaning means for removing transfer residual toner on the secondary image carrier,Arranged downstream of the transfer position by the primary transfer means and the transfer position by the secondary transfer means in the rotational conveyance direction of the secondary image carrier,Application member for applying release agent for easy removal of transfer residual toner to application position on secondary image carrierAnd a cleaning member disposed further downstream of the coating member and provided so as to be able to contact and separate from the secondary image carrier.With,
  in frontWhen applying the release agent, the application member is in contact with the secondary image carrier,
  When the release agent is not applied, the application member is separated from the secondary image carrier after the cleaning member is separated from the secondary image carrier.
[0049]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an overall schematic configuration of an internal mechanism of a simultaneous double-sided image forming printer as an example of a simultaneous double-sided image forming apparatus according to the present invention.
[0050]
The illustrated simultaneous double-sided image forming printer is capable of forming images on both front and back sides of a recording medium P such as paper and OHP film almost simultaneously. As shown in FIG. The image forming apparatuses A, B, C, and D, a primary image carrying apparatus E, a secondary image carrying apparatus F, a recording medium transport apparatus G, a fixing apparatus H, a discharge stack apparatus I, and a toner replenishing apparatus J are provided.
[0051]
The four image forming devices A, B, C, and D form different single-color images using yellow, magenta, cyan, and black toners, respectively, and support drum-shaped image formation that is rotatably supported. The body 12 is arranged in a tandem manner, and a charging unit 13, a developing unit 14, an image forming transfer unit 15, an image forming cleaning unit 16, and an image forming / discharging unit 17 are arranged around each image forming carrier 12. . Under these image forming apparatuses A, B, C, and D, common exposure means 18 for exposing the individual image forming carriers 12 to each other is provided.
[0052]
The image forming carrier 12 is a photoreceptor in which an organic semiconductor layer that is a photoconductive substance is provided on the surface of an aluminum cylinder having a diameter of about 30 to 100 mm. In this example, a drum-like one is used, but a belt-like one may be used.
[0053]
The exposure unit 18 irradiates light from an LD light source (not shown) toward the surface of the image carrier 12 by an optical component (not shown) by a known laser method, and scans the surface of the image carrier 12. To write to it. In this example, a laser method is used, but an exposure method using an LED array and an imaging component may be adopted.
[0054]
The primary image holding device E transfers and supports the images formed by the image forming devices A, B, C, and D, and the belt-like primary image carrier 20 is attached to each image forming carrier 12. In contact with each image forming carrier 12 and each corresponding image forming transfer means 15, it is wound around three primary rollers 21, 22, and 23, and a primary cleaning means 24 and a primary transfer means 25 are arranged around them. is doing.
[0055]
The primary image carrier 20 is a belt based on a resin film or rubber having a thickness of 50 μm to 600 μm, and has a resistance value that allows toner to be transferred from each image forming carrier 12.
[0056]
The secondary image carrier device F is to primarily transfer and carry the image carried by the primary image carrier device E. The secondary image carrier device 30 is brought into contact with the primary image carrier member 20 in contact with the primary image carrier member 20. A predetermined transfer nip is formed between the primary image carrier 20 and the primary transfer means 25, and is wound around three secondary rollers 31, 32, and 33. Means 36 are arranged.
[0057]
Similar to the primary image carrier 20, the secondary image carrier 30 is a belt based on a resin film or rubber having a thickness of 50 μm to 600 μm, and has a resistance value that enables transfer of toner from the primary image carrier 20. Have.
[0058]
The recording medium conveyance device G conveys the recording medium P through a medium conveyance path that passes between the primary image carrying device E and the secondary image carrying device F and extends from the lower side to the upper side in the drawing, and is arranged in two stages, upper and lower. A medium storage container 40 for storing the recording medium P therein, a supply roller 41 for sequentially feeding the recording medium P from the medium storage container 40 one by one from the top, and a medium for guiding the sent recording medium P Guide 42, registration roller 43 that stops by abutting the leading end of recording medium P guided and conveyed by medium guide 42, discharge guide 44 that guides recording medium P after image fixing, and guide by discharge guide 44 And a discharge roller 45 for discharging the recording medium P to be conveyed in the direction of arrow a.
[0059]
The fixing device H fixes a transfer image transferred from the primary image carrying device E and the secondary image carrying device F to the recording medium P, and includes a pair of heating rollers 47.
[0060]
The discharge stack apparatus I stacks the recording medium P after image fixing by the fixing apparatus H, and includes a stack unit 50 formed on the exterior cover 10.
[0061]
The toner replenishing device J replenishes each image forming device A, B, C, and D with a new toner using a powder pump or the like, and includes a toner cartridge 53 for each color in the toner storage portion 52.
[0062]
When the simultaneous double-sided image forming printer forms color images on both the front and back sides of the recording medium P, the image forming carrier 12 and the primary rollers 21, 22, and 23 are controlled based on a print signal from a host (not shown). One, one of the secondary rollers 31, 32, and 33, the supply roller 41, and the like are rotated with timing.
[0063]
In each of the image forming apparatuses A, B, C, and D, as the individual image forming bodies 12 rotate clockwise in the drawing, the surface is uniformly charged by the respective charging means 13, and the common exposure means 18 The individual writing light is used to form a latent image for each color, and each developing unit 14 attaches each color toner to form a toner image for each color on each image forming carrier 12. In the illustrated example, the polarity of the toner on the image forming carrier 12 is negative at this time.
[0064]
In the primary image carrier E, one of the primary rollers 21, 22, and 23 is rotated and the other two rollers are driven to rotate, so that the primary image carrier 20 is synchronized with the image forming carrier 12 in the figure. The image is transferred in a clockwise direction, and a positive charge is applied to the primary image carrier 20 by each image transfer means 15 to sequentially transfer the images on the image carrier 12 and superimpose four colors. A full color image.
[0065]
After the image transfer, the image forming carrier 12 of each of the image forming apparatuses A, B, C, and D removes the transfer residual toner by the image forming cleaning unit 16 and discharges the image by the image forming and discharging unit 17. Thereafter, charging is performed again by each charging unit 13, writing is performed by the exposure unit 18, development is performed by each developing unit 14, and a toner image for each color is formed again on each image forming carrier 12.
[0066]
In the secondary image carrier device F, one of the secondary rollers 31, 32, and 33 is rotated and the other two rollers are driven to rotate so that the secondary image carrier 30 is synchronized with the primary image carrier 20. In the figure, the image is rotated and conveyed clockwise, and a positive charge is applied to the secondary image carrier 30 by the primary transfer means 25 to transfer the image on the primary image carrier 20. At this time, the secondary cleaning means 35 rotates in the direction of arrow b about the support shaft 56 and is in a non-cleaning state.
[0067]
After the image transfer, the primary image carrier 20 of the primary image carrier E removes the transfer residual toner by the primary cleaning unit 24. Thereafter, the images on the image carrier 12 are successively transferred onto the primary image carrier 20 by the respective image transfer means 15 to form a second full-color image in which four colors are superimposed.
[0068]
After the image transfer, the image forming carrier 12 of each of the image forming apparatuses A, B, C, and D removes the transfer residual toner by the image forming cleaning unit 16 and discharges the image by the image forming and discharging unit 17 to perform the next image forming. Prepare for the cycle.
[0069]
On the other hand, in the recording medium transport apparatus G, one of the supply rollers 41 is selectively rotated as appropriate to feed out the recording medium P in the medium storage container 40, guided by the medium guide 42, and the leading end is pushed between the registration rollers 43. The registration roller 43 is rotated in synchronization with the first full-color image and the second full-color image described above, and sent to the transfer nip between the primary image carrier 20 and the secondary image carrier 30.
[0070]
First, a positive charge is applied to the surface of the recording medium P by the primary transfer means 25 to transfer the second full-color image on the primary image carrier 20, and then the recording medium P is conveyed slightly upward when the back surface is transferred. A positive charge is applied to the secondary transfer means 36 to transfer the first full-color image on the secondary image carrier 30. Thereafter, the recording medium P after image transfer on both the front and back surfaces is guided to the fixing device H, and heat and pressure are applied between the pair of heating rollers 47 to fix the transferred images on both sides, and the discharge guide 44 guides and discharges. The sheet is discharged out of the exterior cover 10 by the roller 45 and stacked face down on the stack unit 50 of the discharge stack apparatus I with the surface facing down.
[0071]
Therefore, the second page is formed first as the first full-color image, the first page is formed later as the second full-color image, and the subsequent page is formed first in the same manner, so that the recording medium P The recording medium P can be arranged in the page order on the stack unit 50 by transferring to the back side of the sheet, forming the previous page later, transferring it to the front side, and outputting it face down.
[0072]
At this time, by using a known image processing technique, the second full-color image on the primary image carrier 20 is a normal image on the image carrier 12 and the first full-color image on the secondary image carrier 30. Needs to be a reverse image (mirror image) on the image carrier 12.
[0073]
After the image transfer, the primary image carrier 20 of the primary image carrier E removes the transfer residual toner by the primary cleaning unit 24. The secondary image carrier 30 of the secondary image carrier F rotates the secondary cleaning means 35 around the support shaft 56 in the direction of the arrow c to bring it into a cleaning state. The secondary cleaning means 35 removes the transfer residual toner. Remove and prepare for the next image carrier.
[0074]
When the toner of each developing means 14 is used up, the toner of the same color is replenished by being conveyed from the corresponding toner cartridge 53 of the toner storage portion 52 of the toner replenishing device J by a powder pump or the like.
[0075]
When the conveyance of the recording medium P is hindered by the jam, the front cover 10A of the outer cover 10 is opened in the direction of the arrow d around the support shaft 55, and the medium conveyance path is opened to perform the jam processing.
[0076]
When a full-color image is formed on one side of the recording medium P with this simultaneous double-sided image forming printer, the images formed on the respective image forming bodies 12 of the image forming apparatuses A, B, C, and D are used as primary image carriers E. After the image is transferred to the primary image carrier 20, the image is directly transferred directly to one side of the recording medium P conveyed by the recording medium conveyance device G without being transferred to the secondary image carrier 30 of the secondary image carrier F. Try to transcribe. Then, the transferred image is fixed by the fixing device H, and discharged to the discharge stack device I in the page order in a face-down manner.
[0077]
In addition, when a two-color image or a monochrome image is formed on the recording medium P with the illustrated printer, the image is formed by using the corresponding color image forming device among the four image forming devices A, B, C, and D. Then, the image is transferred to the recording medium P via the primary image carrier 20 of the primary image carrier E and the secondary image carrier 30 of the secondary image carrier F.
[0078]
Next, the secondary cleaning means 35 provided in the simultaneous double-sided image forming printer shown in FIG. 1 will be described in detail with reference to FIG.
[0079]
The secondary cleaning unit 35 includes a release agent solid body 61 in which a release agent 60 that facilitates removal of transfer residual toner on the secondary image carrier 30 is hardened. The release agent solid body 61 contains, for example, zinc stearate and is supported by a bracket (not shown) as a rectangular parallelepiped.
[0080]
The secondary cleaning unit 35 also includes an application member that applies the release agent 60 to the application position Z on the secondary image carrier 30 as, for example, a brush roller 62 that is an example of a rotating body.
[0081]
The brush roller 62 includes, for example, polyester, polypropylene, polyamide, etc., and uses a large number of elastic thin fiber hairs 62B, and the base ends of the hairs 62B are planted on the core material 62C.
[0082]
Such a brush roller 62 is disposed so as to press the tip of the bristles 62B against the release agent solid body 61, and the rotation shaft 62A is rotatably attached to a bracket (not shown). In this example, a brush roller 62 is disposed around the secondary image carrier 30 so that the hair 62B of the brush roller 62 does not contact the surface of the secondary image carrier 30.
[0083]
Then, the brush roller 62 rotates around the rotation shaft 62 </ b> A and applies the scraped release agent 60 to the application position Z while scraping the surface of the release agent solid body 61.
[0084]
Instead of the brush roller 62, a rotating body that is an elastic roller using foaming type rubber may be used as the application member.
[0085]
By the way, if the brush roller 62 is provided above the application position Z as shown in the figure, when the release agent 60 is applied, it can be applied intensively to the application position Z by the action of gravity.
[0086]
Further, if the application position Z is provided in the tangential direction of the brush roller 62 and downstream of the rotation direction indicated by the arrow g, the release agent 60 is concentrated on the application position Z by the action of inertia due to the rotation of the brush roller 62. Can be applied.
[0087]
In addition, the bristles 62B of the brush roller 62 can be prevented from coming into contact with the surface of the secondary image carrier 30, and the bristles 62B of the brush roller 62 can be prevented from being contaminated with the transfer residual toner.
[0088]
Incidentally, such a secondary cleaning means 35 is preferably provided with a cleaning member 63. The cleaning member 63 is made of rubber, for example, and has a blade shape that is slightly wider than the secondary image carrier 30. The front end of the cleaning member 63 is disposed so as to be in contact with the cleaning position Y on the secondary image carrier 30. Then, the brush roller 62, the cleaning member 63, and the like are arranged so that the cleaning position Y comes downstream of the application position Z.
[0089]
In this case, the release agent 60 is applied from the release agent solid body 61 to the application position Z by the brush roller 62 to facilitate the removal of the transfer residual toner, and then the cleaning member 63 performs cleaning at the cleaning position Y. The transfer residual toner on the secondary image carrier 30 can be removed cleanly.
[0090]
Incidentally, another example of the secondary cleaning means 35 is shown in FIG. In the secondary cleaning means 35 shown in FIG. 3, the same components as those shown in FIG.
[0091]
The secondary cleaning unit 35 is provided with a cleaning case 65 that is slightly wider than the width of the secondary image carrier 30. The cleaning case 65 is provided with a blade holder 65A, a release agent solid body holder 65B, a coating member holder (not shown), and a support shaft 56, and the support shaft 56 is rotatably attached to a bracket (not shown).
[0092]
The cleaning member 63 is attached to the blade holder 65A, the release agent solid body 61 is attached to the release agent solid body holder 65B, and the rotating shaft 62A of the brush roller 62 is rotatably attached to the application member holder.
[0093]
The cleaning case 65 includes two plate-like cam holding portions 65C provided substantially in parallel, and a contact / separation mechanism 67 is provided with the cam 66 interposed between the cam holding portions 65C.
[0094]
As described above, if the release agent solid body 61, the brush roller 62, and the cleaning member 63 are provided in one cleaning case 65, it is unnecessary to provide a contact / separation mechanism for each.
[0095]
When the release agent 60 is applied, the cam 66 is rotated, the cleaning case 65 is rotated in the direction of the arrow c about the support shaft 56, and the brush roller is moved to the application position Z on the secondary image carrier 30. 62 is in contact. Thereafter, the cam 66 is further rotated so that the cleaning member 63 is in contact with the cleaning position Y to be in a cleaning state.
[0096]
In this way, the release agent 60 is first applied to facilitate removal of the transfer residual toner, and then the cleaning member 63 performs cleaning, so that the transfer residual toner on the secondary image carrier 30 is cleaned. Can be removed.
[0097]
On the other hand, when the release agent 60 is not applied, the cam 66 is rotated, the cleaning case 65 is rotated in the direction of the arrow b around the support shaft 56, and the cleaning member is moved from the cleaning position Y on the secondary image carrier 30. 63 is separated. Thereafter, the cam 66 is further rotated so that the brush roller 62 is separated from the application position Z to be in a non-cleaning state.
[0098]
In this way, when the secondary image carrier 30 carries the first full-color image, the brush roller 62 and the cleaning member 63 are separated from the secondary image carrier 30 and the release agent 60 is applied. And you can avoid cleaning.
[0099]
In addition, since the cleaning member 63 performs cleaning after always applying the release agent 60, the transfer residual toner on the secondary image carrier 30 can be removed cleanly.
[0100]
Incidentally, another example of the secondary cleaning means 35 is shown in FIG. In the secondary cleaning means 35 shown in FIG. 4, the same components as those shown in FIG. 2 or FIG.
[0101]
The cleaning case 65 is applied to the blade holder 65A, the release agent solid body holder 65B, and the application so that the cleaning position Y of the cleaning member 63 attached to the case 65 is provided upstream of the application position Z of the brush roller 62 attached to the case 65. A member holder is provided.
[0102]
The cleaning member 63 is attached to the blade holder 65A of the cleaning case 65, the release agent solid body 61 is attached to the release agent solid body holder 65B, and the brush roller 62 is attached to the application member holder.
[0103]
When the release agent 60 is applied, the cam 66 is rotated, the cleaning case 65 is rotated in the direction of the arrow c about the support shaft 56, and the cleaning member is moved to the cleaning position Y on the secondary image carrier 30. 63 is in contact. Thereafter, the cam 66 is further rotated so that the brush roller 62 is in contact with the application position Z on the secondary image carrier 30 to obtain a cleaning state.
[0104]
In this way, since the release agent 60 is applied after the cleaning with the cleaning member 63 first, it is possible to prevent the brush roller 62 from being stained with the transfer residual toner.
[0105]
On the other hand, when the release agent 60 is not applied, the cam 66 is rotated, the cleaning case 65 is rotated about the support shaft 56 in the arrow b direction, and the brush roller 62 is separated from the application position Z. Thereafter, the cam 66 is further rotated so that the cleaning member 63 is separated from the cleaning position Y on the secondary image carrier 30 to be in a non-cleaning state.
[0106]
In this way, since the release agent 60 is applied after the cleaning by the cleaning member 63 is always performed, it is possible to prevent the brush roller 62 from being stained with the transfer residual toner.
[0107]
Incidentally, another example of the secondary cleaning means 35 is shown in FIG. In the secondary cleaning means 35 shown in FIG. 5, the same components as those shown in FIG. 2, FIG. 3, or FIG.
[0108]
The secondary cleaning means 35 is provided with the above-described application member and cleaning member as one cleaning application member 70. The cleaning application member 70 includes, for example, a conductive elastic roller, a conductive brush roller, and the like. In the drawing, an example of a brush roller is shown.
[0109]
In order to use the conductive brush roller, for example, the same hair 62B as described above is used, and the hair 70B is attached to the core 70C while the base end of the hair 70B is attached. The rotary shaft 70A is rotatably attached to a bracket (not shown).
[0110]
Then, when applying, cleaning is performed while applying the release agent 60 at the cleaning application position X by rotating the cleaning application member 70 while pressing the tip of the hair 70B of the cleaning application member 70 against the release agent solid body 61. Do.
[0111]
FIG. 6 shows another example of the simultaneous double-sided image forming printer. In the printer shown in FIG. 6, the same components as those shown in FIG. 1 or FIG.
[0112]
The primary cleaning unit 24 of the printer includes a brush roller 59A, a bias roller 59B, a cleaning member 59C, a brush roller 62 (application member), and a release agent solid body 61.
[0113]
When the transfer residual toner on the primary image carrier 20 is removed, the support shaft 56 is rotated, the primary cleaning means 24 is rotated in the direction of arrow c, and the brush roller 62 is pressed against the release agent solid body 61. While rotating the brush roller 62 and applying the release agent 60 at the application position Z, at the same time, the bias roller 59B is charged by a voltage application means (not shown), thereby charging the brush roller 59 to obtain a primary image. The transfer residual toner on the carrier 20 is electrically adsorbed and removed, and the tip of the hair of the brush roller 59A is pressed against the primary image carrier 20, and the surface is scraped off and physically removed.
[0114]
On the other hand, when the secondary image carrier 30 is cleaned, it is physically removed by applying the cleaning member 63 at the cleaning position Y while applying the release agent 60 at the application position Z as described above.
[0115]
As described above, the primary cleaning unit 24 of the primary image carrier 20 electrically and physically removes the transfer residual toner, whereas the secondary cleaning unit 35 of the secondary image carrier 30 is physically The transfer residual toner is removed.
[0116]
  In this wayRemove untransferred tonerCleaning the primary cleaning means 24PerformanceCleaning the secondary cleaning means 35PerformanceTherefore, the transfer performance from the secondary image carrier 30 to the recording medium P can be improved without impairing the transfer performance of the full color image from the primary image carrier 20 to the secondary image carrier 30.
[0117]
By the way, each color toner used in the present invention has an average circularity of 0.90 to 0.99, a shape factor SF-1 of 120 to 180, a shape factor SF-2 of 120 to 190, and a volume average with respect to the number average particle size. When the particle size ratio (Dv / Dn) is 1.05 to 1.30, a high-definition image can be obtained.
[0118]
The average circularity is more preferably 0.93 to 0.97, and the number of particles having a circularity of less than 0.94 is preferably 10% or less. The ratio (Dv / Dn) is more preferably a dry toner having a ratio of 1.10 to 1.25.
[0119]
Here, the average circularity is measured in the following manner using a flow type particle analyzer FPIA-2100 manufactured by Toa Medical Electronics Co., Ltd. That is, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to a container in which 100 to 150 ml of water from which impure solids have been previously removed is placed. Then, about 0.1 to 0.5 g of toner as a measurement sample is added. The suspension in which the toner is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, the dispersion concentration is adjusted to 3000 to 10,000 / μl, and the shape and distribution of the toner are measured by the analyzer. Get by.
[0120]
The following can be said about the average circularity measured in this way.
[0121]
With an irregularly shaped toner having an average circularity of less than 0.90 and too far from a spherical shape, satisfactory transferability and high-quality images without dust cannot be obtained. When the average circularity exceeds 0.99, in a system that employs blade cleaning or the like, poor cleaning occurs on the photosensitive member and the transfer belt, causing stains on the image.
[0122]
For example, when outputting an image with a low image area ratio, there is little transfer residual toner and there is no problem with poor cleaning. However, when outputting an image with a high image area ratio such as a color photographic image, If an untransferred image remains on the photoreceptor due to a defect or the like, a cleaning defect is likely to occur. If the above-mentioned cleaning failures occur frequently, further, the charging roller that contacts and charges the photoreceptor is contaminated, and the original charging ability cannot be exhibited.
[0123]
Further, as shown in FIG. 7, the shape factor SF-1 is a value indicating the ratio of the roundness of the shape of the spherical substance, and the maximum length of the elliptical figure formed by projecting the spherical substance on a two-dimensional plane. This is a value obtained by dividing the square of Q by the figure area X and multiplying by 100π / 4. That is, the shape factor SF-1 is defined by the following equation.
SF-1 = (Q²/ X) × (100π / 4)
[0124]
When the value of SF-1 is 100, the shape of the substance becomes a true sphere, and the larger the value of SF-1, the more unstable the shape of the substance.
[0125]
Further, as shown in FIG. 8, the shape factor SF-2 is a numerical value indicating the ratio of the unevenness of the shape of the substance, and the square of the perimeter P of the figure formed by projecting the substance on the two-dimensional plane is the figure area. It is the value when divided by Y and multiplied by 100 / 4π. That is, the shape factor SF-2 is defined by the following equation.
SF-2 = (P²/ Y) × (100 / 4π)
[0126]
When the value of SF-2 is 100, there is no unevenness on the surface of the substance, and as the value of SF-2 increases, the unevenness on the surface of the substance becomes more prominent. In this example, a toner image was randomly sampled 100 times using an FE-SEM (S-800) manufactured by Hitachi, and the image information was introduced into an image analysis apparatus (LUSEX3) manufactured by Nireco. This is calculated from the above formula.
[0127]
The following can be said about the shape factor SF-1 and the shape factor SF-2 measured in this way.
[0128]
The inventors have clarified that the transfer efficiency increases when the values of SF-1 and SF-2 approach 100 and the shape of the toner approaches a spherical shape. This is due to point contact with other toner particles that contact the toner particles or the image carrier due to the shape effect, so that the fluidity of the toner is increased, or the adsorbing force or the reflection force on the image carrier is weakened. This is considered to be easily affected by the transfer electric field. On the other hand, when the shape of the toner approaches a spherical shape, mechanical cleaning performance such as blade cleaning tends to deteriorate.
[0129]
As described above, this increases the fluidity of the toner, weakens the attracting force or the reflecting force on the image carrier and the like, and the toner easily passes through a slight gap between the cleaning means and the image carrier. It depends. Therefore, from the viewpoint of cleaning performance, the toner shape is somewhat deformed, that is, the value of SF-1 is larger than 100, and has a certain degree of unevenness, that is, the value of SF-2 is larger than 100. preferable.
[0130]
The ratio of the volume average particle diameter to the number average particle diameter is calculated as follows. First, in 100 to 150 ml of about 1% NaCl aqueous solution (for example, ISOTON-II manufactured by Coulter, Inc.) prepared using primary sodium chloride, a surfactant such as alkylbenzene sulfonate as a dispersant is added in an amount of 0.1 to Add 5.0 ml and add 2 to 20 mg of toner to suspend. Next, this suspension is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and the volume and number of toner particles or toner are measured using a 100 μm aperture as an aperture with a particle size distribution measuring device. Calculate distribution and number distribution.
[0131]
From these volume distribution and number distribution, the volume average particle diameter (Dv) and number average particle diameter (Dn) of the toner are obtained, and the ratio of the volume average particle diameter to the number average particle diameter (Dv / Dn) is calculated. In addition, as a particle size distribution measuring apparatus, Coulter Counter TA-II and Coulter Multitizer II manufactured by Coulter are used.
[0132]
Also, the channel is less than 2.00 to less than 2.52 μm, less than 2.52 to 3.17 μm, less than 3.17 to 4.00 μm, less than 4.00 to 5.04 μm, and less than 5.04 to 6.35 μm. 6.35-8.00 μm, 8.00-10.08 μm, 10.08-12.70 μm, 12.70-16.00 μm, 16.00-20.20 μm, 20.20-20 Uses 13 channels of less than 25.40 μm, 25.40 to 32.00 μm, 32.00 to 40.30 μm, and targets particles having a particle size of 2.00 μm or more and less than 40.30 μm.
[0133]
About the ratio (Dv / Dn) of the volume average particle diameter to the number average particle diameter thus measured, the following can be said.
[0134]
In general, it is said that the smaller the toner particle size, the more suitable for obtaining a high-resolution and high-quality image. On the other hand, the transfer performance and the cleaning performance tend to be lowered. Further, when the volume average particle diameter is smaller than the range of the present invention, in the two-component developer, the toner is fused to the surface of the carrier during a long period of stirring in the developing device, and the charging ability of the carrier is lowered.
[0135]
When used as a one-component developer, toner filming on the developing roller and toner fusion to a member such as a blade for thinning the toner are likely to occur. These phenomena are the same for the toner having a fine powder content higher than the range of the present invention. On the contrary, when the volume average particle diameter of the toner is larger than the range of the present invention, it becomes difficult to obtain a high-resolution and high-quality image and the balance of the toner in the developer is performed. In many cases, the variation in the particle diameter of the toner increases.
[0136]
It was also clarified that the same is true when the volume average particle diameter / number average particle diameter (Dv / Dn) is larger than 1.30. When the volume average particle diameter / number average particle diameter is smaller than 1.05, there are some aspects that are preferable from the viewpoint of stabilizing the behavior of the toner and uniformizing the charge amount. In addition, it is difficult to separate the functions depending on the toner particle size, such as developing a solid image mainly with large-size particles.
[0137]
Therefore, the volume average particle diameter (Dv) of the toner is 4 to 8 μm, and the ratio of the volume average particle diameter to the number average particle diameter (Dv / Dn) is 1.05 to 1.30, preferably 1.10 to 1. .25, the toner particle size distribution becomes narrow, and the following effects can be obtained.
[0138]
First, since selective development in which toner particles having a toner particle diameter corresponding to an image pattern are selectively developed is less likely to occur, a stable image can always be formed. In addition, since the particle size distribution of the toner is narrowed, it is less susceptible to the effect that occurs when a toner recycling system is mounted, that is, the effect that many small-sized toner particles that are difficult to transfer are recycled in quantity, and is always stable. An image can be formed.
[0139]
Furthermore, in the case of a two-component developer, even if a long-term balance of toner is performed, fluctuations in the toner particle diameter in the developer are reduced, and good and stable developability can be obtained even with long-term stirring in the developing device. It is done. In addition, even when used as a one-component developer, even if the balance of the toner is performed, fluctuations in the particle diameter of the toner are reduced, and the filming of the toner on the developing roller and the toner layer are reduced. Therefore, the toner is not fused to a member such as a blade, and good and stable developability and an image can be obtained even when the developing device is used for a long time by stirring or the like.
[0140]
In addition, the average circularity, the shape factor SF-1, the shape factor SF-2, and the volume average particle size with respect to the number average particle size do not have to be all within the above numerical range, and any one of the numerical values may be used. If it exists in the said range, a high-definition image can be obtained.
[0141]
  As explained above, claim 1And 2According to the invention, the secondary cleaning unit that removes the transfer residual toner on the secondary image carrier applies the release agent that facilitates the removal of the transfer residual toner to the application position on the secondary image carrier. Since it has an application member, it can be cleaned after applying a release agent to the transfer residual toner to facilitate removal, and image transfer can be performed by cleanly removing the transfer residual toner on the secondary image carrier of the simultaneous double-sided image forming apparatus. Can be good.
[0149]
  Claim1 and 2According to the invention according toAlso,The secondary cleaning means is provided with a contact / separation mechanism so that when the release agent is applied, the application member is in contact with the secondary image carrier, and when the release agent is not applied, the application member is separated from the secondary image carrier. Therefore, when there is a first image on the secondary image carrier, the coating member is separated from the secondary image carrier and no release agent is applied. Since the influence on the first image is reduced, image formation can be further improved.
[0152]
  Claim1According to the invention according toin addition,When the release agent is applied, the application member comes into contact with the secondary image carrier, and then the cleaning member comes into contact. Therefore, after the release agent is applied first, cleaning is performed with the cleaning member. Image formation can be further improved by removing the transfer residual toner above more cleanly.
[0153]
  Claim2According to the invention according toin addition,When the release agent is not applied, since the cleaning member is separated from the secondary image carrier and then the application member is separated, the release member is always applied, and then the cleaning member is used to perform cleaning on the secondary image carrier. Image formation can be further improved by removing the transfer residual toner more cleanly.
[Brief description of the drawings]
FIG. 1 is an overall schematic configuration diagram of a printer as an example of a simultaneous double-sided image forming apparatus according to the present invention.
FIG. 2 is an example of a configuration diagram of secondary cleaning means provided in the printer.
FIG. 3 is another configuration diagram of secondary cleaning means provided in the printer.
FIG. 4 is another configuration diagram of secondary cleaning means provided in the printer.
FIG. 5 is still another configuration diagram of secondary cleaning means provided in the printer.
FIG. 6 is an overall schematic configuration diagram of another example of a printer according to the present invention.
FIG. 7 is an explanatory diagram showing the maximum length of an elliptical figure formed by projecting a spherical substance on a two-dimensional plane.
FIG. 8 is an explanatory diagram showing the perimeter of a substance.
FIG. 9 is an overall schematic configuration diagram of a conventional printer.
[Explanation of symbols]
20 Primary image carrier
24 Primary cleaning means
25 Primary transfer means
30 Secondary image carrier
35 Secondary cleaning means
36 Secondary transfer means
60 Release agent
61 Release agent solid
62 Brush roller (application member)
63 Cleaning member
65 Cleaning case
67 Contact / separation mechanism
70 Cleaning application member
P Recording medium
Y Cleaning position
Z application position

Claims (2)

After the first image carried on the primary image carrier is transferred to the secondary image carrier by the primary transfer means, a second image is separately carried on the primary image carrier, and the second image is transferred to the secondary image carrier. In a simultaneous double-sided image forming apparatus that forms images on both sides of a recording medium by transferring the first image by a secondary transfer unit by a primary transfer unit,
Secondary cleaning means for removing transfer residual toner on the secondary image carrier is disposed downstream of the transfer position by the primary transfer means and the transfer position by the secondary transfer means in the rotational conveyance direction of the secondary image carrier. And an application member for applying a release agent for facilitating removal of the transfer residual toner to the application position on the secondary image carrier , and further arranged downstream of the application member. And a cleaning member provided so as to be able to come in contact with and away from ,
When applying the pre-Symbol release agent, after the coating member in contact with the secondary image bearing member, as the cleaning member is in contact,
The simultaneous double-sided image forming apparatus, wherein when the release agent is not applied, the application member is separated from the secondary image carrier. After the first image carried on the primary image carrier is transferred to the secondary image carrier by the primary transfer means, a second image is separately carried on the primary image carrier, and the second image is transferred to the secondary image carrier. In a simultaneous double-sided image forming apparatus that forms images on both sides of a recording medium by transferring the first image by a secondary transfer unit by a primary transfer unit,
Secondary cleaning means for removing transfer residual toner on the secondary image carrier is disposed downstream of the transfer position by the primary transfer means and the transfer position by the secondary transfer means in the rotational conveyance direction of the secondary image carrier. And an application member for applying a release agent for facilitating removal of the transfer residual toner to the application position on the secondary image carrier , and further arranged downstream of the application member. And a cleaning member provided so as to be able to come in contact with and away from ,
When applying the pre-Symbol release agent, wherein the coating member is in contact with the secondary image bearing member,
The simultaneous double-sided image forming apparatus, wherein when the release agent is not applied, the application member is separated from the secondary image carrier after the cleaning member is separated from the secondary image carrier.

Images