Patent Grant
8346144
The present invention relates to an electrophotographic type image forming apparatus, such as a laser printer and a copying machine, and particularly, it relates to a control for cleaning means for cleaning the surface of a fixing member of a fixing means for heating and melting toner and fixing it on a recording material.
In an image forming apparatus for forming an image on a recording material using an electrophotographic system, the image forming apparatus that has a frameless printing function for forming an image on an entire area of the recording material is known. For example, Japanese Laid-open Patent Application 2007-199389 discloses an apparatus, in which a toner image larger than the recording material is formed on an image bearing member and an intermediary transfer member, the toner image is transferred onto the entire area of the recording material, and the toner image on the recording material is nipped and fed by a fixing nip of a fixing device to be fixed on the recording material. Here, in the fixing nip of the fixing device, in nipping and feeding the recording material, the toner may be deposited on a fixing member (a fixing roller, a fixing film, and a pressing roller or the like) which forms the fixing nip, and the deposited toner may contaminate the recording material.
Referring to (a) and (b) of
In such a case, as shown in (b) of
In order to avoid an image defect by the toner contamination of the fixing device at the time of such a frameless printing, for example in Japanese Laid-open Patent Application 2007-304180, a cleaning member for cleaning the fixing member which constitutes the fixing nip is provided. The cleaning member comprises a cleaning roller composed of a solid aluminum and a felt cleaning pad of a heat resistive fiber, for example, and it is pressed against the fixing member to remove the contamination, such as the toner or a paper dust, deposited on the fixing member.
In Japanese Laid-open Patent Application 2007-304180, since the cleaning member continues contacting the fixing member, the toner contamination deposited on a recording material cut end portion can be prevented, at the time of the frameless printing. However, the amount of the collectable toner by cleaning member has a limitation, and in the case where this limitation is reached, the cleaning power decreases, with the result that the contamination remains on the fixing member. Then, the cleaning member discharges the contamination to contaminate the fixing member, with the result that a satisfactory cleaning property is not assured. Therefore, in the case where the cleaning means is provided in a fixing portion, it is important that the cleaning means is used in a range capable of collecting the toner.
As a method of solving such a problem, Japanese Laid-open Patent Application Hei 5-224555, for example discloses that the timing at which the cleaning member contacts the fixing member is limited, to reduce the amount of the toner collected by the cleaning means. More specifically, during the sheet processing of the recording material, the cleaning member is spaced from the fixing member, and the cleaning member is contacted to the fixing member at a timing other than during the sheet processing of the recording material. By this, the toner contamination deposited on the fixing member during the sheet processing of the recording material is not collected by the cleaning member, but it is collected by the passing recording material per se (self cleaning).
The cleaning member removes the toner contamination deposited on the fixing member after the self cleaning by the recording material, and therefore, the amount of the toner collected by the cleaning member can be reduced also during the sheet processing of the recording material, as compared with the case of the contact. Therefore, the time at which the cleaning member reaches the limits (toner saturation zone) of its cleaning and collecting capability can be delayed, and the lifetime of the cleaning means can be prolonged, and therefore the running cost of the apparatus can be reduced.
However, in Japanese Laid-open Patent Application Hei 5-224555, the cleaning member is spaced from the fixing member during the sheet processing, and therefore, the toner contamination attributable to the offset of the toner deposited on the recording material cut end portion at the time of the frameless printing cannot be prevented. More particularly, as shown in (a) and (b) of
Particularly, at the time of the frameless printing, in the case where the toner 11t deposited on the cut end portion 11b of the leading end or the trailing end of the recording material is deposited on the heating roller 31 which is the fixing member, it appears as an image defect in the form of horizontal lines on the recording material 11, as shown in (b) of
On the other hand, in the case where the cleaning member continues contacting the fixing member during sheet processing, as shown in Japanese Laid-open Patent Application 2007-304180, the toner contamination deposited on the recording material cut end portion at the time of the frameless printing can be prevented. However, the opportunity for the self cleaning by the recording material disclosed in Japanese Laid-open Patent Application Hei 5-224555 is lost, and therefore, the toner collection amount by the cleaning member is large. Furthermore, the toner saturation zone is reached sooner, and therefore, the life of the cleaning member is shortened.
An object of the present invention is to provide an image forming apparatus in which the lifetime reduction of a cleaner can be suppressed.
Another object of the present invention is to provide an image forming apparatus, in which the toner contamination of the fixing member attributable to the toner deposited on a cut end portion of a transfer material at the time of the frameless printing can be eliminated, and a self cleaning function by the transfer material can be utilized, by which the prolongation of the life of the cleaning means can be accomplished. According to an aspect of the present invention, there is provided an image forming apparatus comprising an image forming apparatus comprising: an image forming station for forming an unfixed toner image on a recording material; a fixing station for fixing the unfixed toner image on the recording material, the fixing station including a rotatable member for forming a fixing nip for nipping and feeding the recording material, and a cleaner, movable toward and away from the rotatable member, for cleaning the rotatable member. The apparatus is operable in a frameless or blankless image formation mode for forming the toner image without a frame or blank at least at one of a leading end and a trailing end of the recording material. The cleaner contacts the rotatable member at a time at which a portion of the rotatable member that has contacted a blankless range (marginal or frame area in the case of the printing with blank or a frame) at the leading end or the trailing end of the recording material reaches a position where the portion opposes the cleaner. The cleaner also is spaced from the rotatable member in a period in which a portion of the rotatable member that has contacted the recording material in a range other than the blankless range passes the position where the portion opposes said cleaner.
According to the present invention the prolongation of the life of the cleaning means is accomplished.
These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings.
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings.
The image forming station forms a color image, and more particularly, an electrostatic latent image is formed by the exposure light applied on the basis of the exposure times modulated by the image processing station, and the electrostatic latent image is developed into a monochromatic toner image, and the plurality of monochromatic toner images are overlaid into a multicolor toner image. The multicolor toner image is transferred onto a recording material 11 fed from a feeding portion, and the multicolor toner image on the recording material 11 is fixed by the fixing portion 30.
Each image forming station comprises a photosensitive drum (22Y, 22M, 22C, 22K), an injection charger (23Y, 23M, 23C, 23K), a scanner portion (24Y, 24M, 24C, 24K), a toner cartridge (25Y, 25M, 25C, 25K), a developing portion (26Y, 26M, 26C, 26K), and a primary transfer roller (27Y, 27M, 27C, 27K). Also provided are an intermediary transfer member 28 and a secondary transfer roller at positions 29a and 29b. Moreover, also provided are a secondary transfer roller cleaning member for cleaning the secondary transfer roller at positions 29a, 29b and an intermediary transfer member cleaning member 40 for cleaning the intermediary transfer member 28.
A feeding system from the feeding portion to the fixing portion 30 comprises a registration roller 51, a pre-registration sensor 52, and a sheet discharging roller 61. The operation of the image forming station, the feeding portion, the fixing portion 30, and the feeding system are controlled by CPU 200. A feeding speed V of the recording material 11 is the approximately 200 mm/sec, for example. Each of the photosensitive drums (photosensitive members) 22Y, 22M, 22C, 22K includes an aluminum cylinder, an outer periphery of which is coated with an organic photoconductive layer, and it is rotated by a driving force from the unshown driving motor. The driving motor rotates the photosensitive drums 22Y, 22M, 22C, 22K in a counter-clockwise direction in accordance with the image forming operation.
The injection chargers 23Y, 23M, 23C, 23K of the image forming station are primary charging means, and the photosensitive drums for the yellow (Y), the magenta (M), the cyan (C), and the black (K) colors are charged. Each of the injection chargers 23Y, 23M, 23C, 23K is provided with a sleeve 23YS, 23MS, 23CS, 23KS, respectively. The exposure light to the photosensitive drums 22Y, 22M, 22C, 22K is sent from the scanner portions 24Y, 24M, 24C, 24K, respectively, and selectively exposes the surfaces of the photosensitive drums 22Y, 22M, 22C, 22K. By this, the electrostatic latent images are formed on the photosensitive drums 22Y, 22M, 22C, 22K, respectively.
In the developing portion, there are provided developing devices for the yellow (Y), magenta (M), cyan (C), and black (K) development 26Y, 26M, 26C, 26K for the stations to visualize the electrostatic latent images, respectively. Each of the developing devices 26Y, 26M, 26C, 26K includes a developing sleeve 26YS, 26MS, 26CS, 26KS, respectively. Developing biases are applied between the developing sleeves 26YS, 26MS, 26CS, 26KS and the corresponding photosensitive drums 22Y, 22M, 22C, 22K, respectively, from an unshown voltage source. Each of the developing devices 26Y, 26M, 26C, 26K can be dismounted.
The intermediary transfer member 28 is contacted to the photosensitive drums 22Y, 22M, 22C, 22K, and is rotated clockwise at the time of a color image formation, together with the rotations of the photosensitive drums 22Y, 22M, 22C, 22K so that four monochromatic toner images are transferred thereonto. The primary transfer bias voltages are applied between the primary transfer rollers 27Y, 27M, 27C, 27K and the corresponding photosensitive drums 22Y, 22M, 22C, 22K, respectively, from the unshown voltage source.
In the feeding portion, there is provided a sheet feeding cassette 21a or a sheet feeding tray 21b, which contains the recording materials 11. The recording material 11 is fed to the registration roller 51 by feeding rollers 20. A position of the recording material 11 is detected by the pre-registration sensor 52. The pre-registration sensor 52 is disposed in front of the registration roller. The pre-registration sensor 52 is comprises a LED and a photodetector for detecting the reflected light therefrom. When the recording material 11 reaches the neighborhood of a pre-registration sensor 52, the photodetector detects the reflected light from the LED, so that an on-state is determined, and when the recording material 11 is not adjacent to the pre-registration sensor 52, the photodetector does not detect the light, and therefore, the off-state is determined. At the time of an image formation, the feeding of the recording material 11 is stopped for predetermined time duration, corresponding to the time, the multicolor toner image on the intermediary transfer member 28 reaches the transfer roller at positions 29a, 29b, by the pre-registration sensor 52. The recording material 11 reaches the secondary transfer roller at positions 29a, 29b from the registration roller 51.
The secondary transfer roller at positions 29a, 29b contacts the intermediary transfer member 28 and the recording material 11 is nipped and fed to transfer the multicolor toner image from the intermediary transfer member 28 onto the recording material 11, and the recording material 11 is fed to the fixing portion 30. During the transferring of the multicolor toner image onto the recording material 11, the secondary transfer roller is contacted to the recording material 11 at the position 29a, and is spaced to the position 29b after the printing process. A secondary transfer bias voltage is applied between the secondary transfer roller and an intermediary transfer member 28 from the unshown voltage source. The secondary transfer roller cleaning member 100 scrapes the contamination of the secondary transfer roller off to clean it, and it is made of a urethane rubber blade.
The fixing portion 30 is provided with a fixing roller 31 and a pressing roller 32 which are a pair of fixing members which form a fixing nip for heat-fixing the toner image on the recording material, and while it feeds the recording material 11, it fuses and fixes the transferred multicolor toner image. The fixing roller 31 heats the recording material 11, and the pressing roller 32 press-contacts the recording material 11 to the fixing roller 31. The recording material 11 which stores the multicolor toner image receives the heat and the pressure by the fixing roller 31 and the pressing roller 32, so that the toner is fixed on the surface, and the recording material 11 is fed to the sheet discharging roller 61. The sheet discharging roller 61 discharges the recording material 11 to an unshown sheet discharge tray, and the image forming station finishes a series of image forming operations.
A description will be provided as to printing operations in a print mode with the blank, and frameless printing mode according to this embodiment. In this image forming apparatus, in the case where it carries out printing in the print mode with the blank or frame on the recording material 11, as shown in (a) of
In the case where the image is formed in frameless printing mode on the recording material 11, as shown in (b) of
On the other hand, in a secondary transfer portion, as shown in (a) of
In this embodiment, the offset toner, produced by the toner deposited on the cut end portion of the leading end and the trailing end of the recording material, is removed, by which the image defect is prevented, and, a self cleaning by the recording material by itself can be performed. Here, a detailed description will be provided as to the fixing portion in the image forming apparatus according to this Embodiment 30.
The fixing roller 31 has a hollow metal core 31a as a base layer, which is coated with an elastic layer. For example, the metal core 31a has a thickness of 2.0 mm, is made of Fe, and is coated with a silicone rubber of 2 mm thick. The outermost layer is composed of a fluorinated resin material of a thickness of 50 micrometers, as a toner parting layer. The fixing roller 31 has an outer diameter of 35 mm. The pressing roller 32 has the structure similar to the fixing roller 31. It has an Fe hollow metal core 31a of a thickness of 2.0 mm as the base layer, which is coated with silicone rubber as the elastic layer having a thickness of 2 mm. The outermost layer is composed of a fluorinated resin material of a thickness of 50 micrometers as a toner parting layer. The outer diameter of the pressing roller 32 is 35 mm similarly to the fixing roller 31. The pressing roller 32 forms a fixing nip N for pressing at a predetermined pressure relative to the fixing roller 31, and heating and melting the toner onto the recording material 11, by an unshown spring and a supporting member.
The fixing roller 31 and the pressing roller 32 have hollow configurations, and the insides thereof are provided with the heaters 33, 34 such as a halogen heater. The heater 33 and 34 heat the fixing roller 31 and the pressing roller 32, respectively. The surface temperatures of the fixing roller 31 and the pressing roller 32 are detected by thermopiles 73, 74 which are non-contact type temperature sensors, respectively. The thermopiles 73, 74 are disposed opposed to a roller surface, and the data detected by thermopiles 73, 74 is converted by A/D conversion with the CPU 200. The CPU200 determines the ON/OFF state of the halogen heaters 33, 34 based on the result of the temperature detection to carry out the temperature control, so that the surface temperatures of the fixing roller 31 and the pressing roller 32 are maintained at the predetermined temperature (approx. 180□).
Each of the cleaning rollers 35, 36 as the cleaning means has the aluminum pipe, which is coated with a nonwoven fabric of the thickness of 2 mm and is made of by aramid resin fiber, and the outer diameter thereof is 9 mm. At predetermined timing as will be described hereinafter, the cleaning rollers 35, 36 are contacted at a predetermined pressure relative to the fixing roller 31 or the pressing roller 32, and the toner contaminating the roller is attracted to the cleaning rollers 35, 36 and those rollers are cleaned. Here, referring to
The cleaning rollers 35, 36 are disposed on the downstream sides of the fixing nip N formed by the fixing roller 31 and the pressing roller 32 with respect to the respective peripheral surface movement directions, and the circumferential distances from the fixing nip N are the same. The cleaning rollers 35, 36 are rotatably supported by the frames 72, 82, respectively, using flanges for the supporting shafts press-fitted into the opposite ends of an aluminum pipe. Ends of frames 72, 82 are rotatable relative to the shafts 71, 81 provided in a fixing portion frame 80. By rotating the frames 72, 82 about the shafts 71, 81, the cleaning rollers 35, 36 are contacted to and spaced from the fixing roller 31 and the pressing roller 32, respectively.
A contacting and spacing state of each of the cleaning rollers 35, 36 is controlled by the cams 74, 84, respectively, which constitute a part of fixing cleaning control means of
When the cams 74 and 84 rotate to predetermined spaced positions, the frames 72 are 82 are pushed up so that the contact, to the fixing roller 31 and the pressing roller 32, of the cleaning rollers 35, 36, respectively, is released to be capable of being spaced. Designated by reference characters 35b, 36b are the spacing positions of the cleaning rollers 35, 36, respectively ((b) of
Referring to
Step1: When the image forming apparatus is in a stand-by ready state, the cleaning rollers 35, 36 are in the spacing state ((b) of
At the timing of iii, the contact/separating operation of the cleaning rollers 35, 36 is controlled in accordance with the operation timing of ta, tb, tc shown in step 4 of
The time tb is the feeding time calculated on the basis of the length, with respect to the feeding direction, of the recording material 11 and the feeding speed. The cleaning rollers 35, 36 are shifted to a second contact state at the timing ta+tb at which the toner contamination of the recording material trailing end deposited on the fixing roller 31 or the pressing roller 32 reaches the contact positions of the cleaning rollers 35, 36. The time tc is a contact period of the cleaning rollers 35, 36, and after the elapse of the time tc, the cleaning rollers 35, 36 return to the spacing states. In state i, when CPU200 in the image forming apparatus receives the printing signal, and, in the case where the print mode with the blank is selected, ((b) of
Table 1 shows a comparison in the property with respect to the items 1)-5) in the comparison examples 1, 2 and this embodiment. Comparison example 1 is a cleanerless system. In comparison example 2, the cleaning roller according to the embodiment is normally contacted, and Embodiment 1 in this embodiment. In the Embodiment 1, ta=0.5 sec, tb=0.5 sec (recording material length=100 mm, feeding speed=from 200 mm/sec), tc=0.1 sec. In the Table, items 2) and 4) are an actual measurement data of amounts of toner depositions to each cleaning roller per one recording material. These are the results of the case in which the toner amount per unit area in the additional printing area is 1.2 mg/cm2 in this embodiment. Item 3) and 5) are the durable lifetime numbers of the cleaning roller, which are calculated based on the actual measurements of 2) and 4) and a cleaning capacity (toner amount which the cleaning roller can collect) of the cleaning roller in the embodiment.
A description will be provided as to item 1) which indicates the presence or absence of the production of the image defect due to the offset toner in the leading end and the trailing end of the recording material at the time of the frameless printing. In the case of the comparison example 1, since the cleaning roller, which is the cleaning means, is not employed, an image defect occurs. However, in the case of the comparison example 2 and Embodiment 1, the cleaning roller which is the cleaning means is employed, and the toner contamination can be removed, and therefore, the image defect does not occur. The amount of toner depositions to each cleaning roller (item 2) and 4)) is smaller than in the comparison example 2 in Embodiment 1. In Embodiment 1, the contact timing of the cleaning roller is limited and the toner contamination on the surface of paper is removed by the self cleaning. By this, as shown in the comparison example 2, the toner collection amount decreases as compared with the case of always contacting the cleaning roller which is the cleaning means. As a result, it is understood that the durable lifetime number of sheets produces using items 3) and 5) of each cleaning roller in Embodiment 1 is much larger than in the comparison example 2, and therefore, the life time prolongation of the cleaning roller can be accomplished.
As has been described in the foregoing, by a cleaning control by the cleaning roller of the fixing portion employed in this embodiment, an image defect (offset) attributable to the offset toner deposited on the cut end portions of the leading end and a trailing end of the recording material at the time of the frameless printing can be prevented. By this, satisfactory images can be provided. As to the toner contamination that occurs from causes other than roller contact with the leading end and the trailing end of the recording material, the cleaning rollers 35, 36 are spaced from the fixing roller 31 and the pressing roller 32, respectively, and the toner contamination is removed by the self cleaning of the recording material by itself. For this reason, the toner deposition to the cleaning rollers 35, 36 can be reduced. Therefore, the cleaner reaches the toner saturation zone later. As a result, the life time prolongation and the reduction of a replacement cycle can be accomplished.
The image forming apparatus relating to Embodiment 2 of the present invention will be described. In the description of this embodiment, the same reference numerals as in Embodiment 1 are assigned to the elements having the corresponding functions in this embodiment, and the detailed description thereof is omitted for simplicity. In this embodiment, operation control of the fixing portion 30 is different from Embodiment 1, and in this embodiment, the pre-registration sensor 52 functioning as the recording material detecting means is used for the purpose of the improvement of the accuracy of the timing of the contact/spacing of the cleaning rollers 35, 36. The pre-registration sensor 52 is provided before the fixing portion in the sheet passage. More particularly pass timing of the recording material is detected by the pre-registration sensor 52, and the contact timing of the cleaning rollers 35, 36 is determined on the basis of the result of detection.
Referring to
Step 1: When the image forming apparatus is in the stand-by ready state, the cleaning rollers 35, 36 are in the spacing states ((b) of
Step 2: The stand-by ready state is continued until the printing signal is received.
Step 3: When the printing signal is received, the different control is carried out, depending on whether the signal thereof designates a frameless printing mode, or a print mode with a frame or blank.
Step 4: In the case where the frameless printing mode is designated, CPU200 sets cleaning roller set times tc and tr. Tc is similar to Embodiment 1, and tr is a constant stored in ROM in CPU200. The time tc is the feeding time determined on the basis of the length from the pre-registration sensor 52 to the contact positions of the cleaning rollers 35 and 36 in the fixing portion (30) in the feeding direction.
Step 5: The frameless printing operation of the image forming apparatus in the present Embodiment 2 is executed.
Step 6: After the printing operation execution, the recording material 11 is fed from the feeding portion, and timing Tx1 at which the pre-registration sensor 52 becomes ON is detected.
Step 7: Tx2 is the timing tr after the timing Tx1.
Step 8: After the printing operation execution, the recording material 11 is fed from the feeding portion, and timing Ty1 at which it becomes again Off is detected after the pre-registration sensor 52 once becomes On.
Step 9: Ty2 is the timing tr after the timing Ty1.
Step 10: The blank printing operation of the image forming apparatus in this embodiment is executed. In this case, the cleaning rollers are normally spaced from the fixing roller and the pressing roller.
Step 11: When the frameless printing operation or the blank printing operation is completed, the operation returns to the stand-by ready state Step 1.
At the timing 1, as a result of the CPU200 in the image forming apparatus receiving the printing signal, when blank print mode is set, (
The table 2 shows the defective image incidences per 10000 of the processed recording materials 11 in Embodiment 1 and Embodiment 2. Here, only the off-set toner contamination at the cut end portion of the leading end and the trailing end of the recording material counts as the image defect. In this embodiment, tc=0.1 sec, and tr=0.4 sec.
From table 2, it is understood that the defective image incidence is lower in Embodiment 2 than in Embodiment 1. This is because the leading end and the trailing end of the recording material is detected using the pre-registration sensor 52, by which the contact timing of the cleaning rollers 35, 36 relative to the fixing roller 31 and the pressing roller 32 is determined with higher accuracy. In the present Embodiment 2, the cleaning control by the cleaning rollers 35, 36 is carried out on the basis of the result of detection of the pre-registration sensor 52, by which the cleaning of the fixing roller 31 and the pressing roller 32 can be carried out more assuredly and accurately than in Embodiment 1. As a result, a larger number of image defects caused by the offset toner at the cut end portion at the leading end and the trailing end of the recording material is prevented.
The image forming apparatus according to Embodiment 3 of the present invention will be described. as shown in
Referring to
Step 1: When the image forming apparatus is in the stand-by ready state, the cleaning rollers 35, 36 are in the spacing state ((b) of
Step 2: The stand-by ready state is continued until the printing signal is received.
Step 3: When the printing signal is received, different control is carried out depending on whether the signal designates the frameless printing mode or designates a blank print mode.
Step 4: In the case where frameless printing mode is designated, CPU200 sets the cleaning roller set times tc, tf. tc is similar to tc in Embodiment 1 and Embodiment 2. Time tf is a constant stored in ROM in CPU200, and it is a feeding time determined on the basis of the length, with respect to the feeding direction, from the contact position of the cleaning rollers 35, 36 to the fixing portion 30 from the pre-fixing sensor 53.
Step 5: The frameless printing operation of the image forming apparatus in this embodiment is executed.
Step 6: After the printing operation execution, the recording material 11 is fed from the feeding portion, and the timing at which the pre-fixing sensor 53 becomes On T′x1 is detected.
Step 7: T′x2 is the timing tf after the timing T′x1.
Step 8: The recording material 11 is fed from the feeding portion 21 after the printing operation execution, and timing T′y1 at which it becomes again Off is detected after the pre-fixing sensor 53 once becomes ON.
Step 9: T′y2 is the timing tf after the timing T′y1.
Step 10: on the other hand, in the case where blank print mode is designated, only the fixing roller 31 and the pressing roller 32 start the rotation, while the cleaning rollers 35, 36 are in the spacing state from the fixing roller 31 and the pressing roller 32, and the printing operation with the blank is executed.
Step 11: When the frameless printing operation or the printing operation with the blank is completed, the operation returns to the stand-by ready state Step1.
At timing i, the CPU 200 in the image forming apparatus receives the printing signal, and as a result, when print mode with the blank is set ((b) of
From Table 3, it is understood that the defective image incidence is lower in Embodiment 3 than in Embodiment 1 and Embodiment 2. In this embodiment, the pre-fixing sensor 53 provided just before the fixing portion 30 is used, and the leading end and the trailing end of the recording material is detected thereby. By this, as compared with the control on the basis of the printing signal in Embodiment 1, and the control on the basis of the pre-registration sensor 52 in Embodiment 2, the contact timing, relative to the fixing member, of the cleaning rollers 35, 36 can be controlled with even better accuracy.
As has been described in the foregoing, in the present Embodiment 3, the cleaning control of the cleaning rollers 35, 36 is carried out on the basis of the result of detection of the pre-fixing sensor 53. As a result, the fixing member can be cleaned more correctly and assuredly than in Embodiment 1 and Embodiment 2, and the image defect, due to the offset toner of the cut end portions of the leading end and the trailing end, of the recording material can be prevented. As the frameless printing function, in each of the above-described embodiments, the frameless printing is executed for both the leading end and the trailing end, with respect to the feeding direction, of the recording material, but the present invention is not limited to this, and the frameless printing may be executed only for the leading end or only for the rear end portion, with respect to the feeding direction, of the recording material. Both of the fixing roller 31 and the pressing roller 32 are cleaned by the cleaning rollers 35, 36 in the above-described embodiments, but a cleaning roller which is contacted to and spaced relative to only one of the fixing roller 31 and the pressing roller 32 may be provided to clean only one of the roller surface.
While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modification or changes as may come within the purposes of the improvements or the scope of the following claims.
This application claims priority from Japanese Patent Application No. 138291/2009 filed Jun. 9, 2009, which is hereby incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-138291 | Jun 2009 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 7178891 | Takamiya | Feb 2007 | B2 |
| 7623820 | Nada et al. | Nov 2009 | B2 |
| Number | Date | Country |
|---|---|---|
| 5-224555 | Sep 1993 | JP |
| 9-80956 | Mar 1997 | JP |
| 2001-5325 | Jan 2001 | JP |
| 2007-199389 | Aug 2007 | JP |
| 2007-232899 | Sep 2007 | JP |
| 2070-304180 | Nov 2007 | JP |
| 2008-281606 | Nov 2008 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20100310288 A1 | Dec 2010 | US |
