JP4085628B2 - Image forming apparatus - Google Patents

Description

【００６１】
つまり、調整ＮＶＭ値は、次に数２式で与えられる。
なお、数値は、少数点以下を四捨五入し、整数とする。
また、湿度センサーの異常が発生したときには、Ａ＝０とする。
【００６２】
【数２】

【００６３】
３．また、セールスエンジニアが２．の調整ＮＶＭ値を変更することが可能となっている。つまり、（用紙坪量・用紙サイズ・普通紙／コート紙毎のデータ）及びＡの値が変更可能となっている。
４．さらに、セールスエンジニアが特殊モードから入力できるオフセットＮＶＭを備えており、これは、調整ＮＶＭ全体を一定量だけオフセットさせることが可能となっている。平行度調整動作は、常にオフセットＮＶＭ＋調整ＮＶＭの合計値が±２００ステップを超えないようになっている。
５．また、記録用紙３４を収容した各トレイごとに、サービスエンジニアが特殊モードから入力できるトレイオフセットＮＶＭを備えており、選択済のオフセットＮＶＭ＋調整ＮＶＭの値に対して微調整が可能となっている。なお、トレイオフセットＮＶＭ＋オフセットＮＶＭ＋調整ＮＶＭの合計値は、±２００ステップを超えないようになっている。
６．湿度のサンプリング間隔は、約５分に設定されている。
７．また、湿度のサンプリグ結果の反映時期は、できるだけ早い時期に実施するように設定されている。
８．さらに、各種用紙情報の反映時期は、画像形成装置が稼働中であっても、二次転写が実行される前に完了するようになっている。
【００６４】
このように、本実施の形態に係る画像形成装置では、用紙や環境に変化が合った場合は、コピージョブ中であっても、調整ＮＶＭ等に記憶されたテーブルからデータを読み出し、駆動モータ６９の回転量を制御することによって、バックアップロール３１の中間転写ベルト２５の移動方向と直交する方向への変位量を調整し、当該中間転写ベルト２５から記録用紙３４上に転写されるトナー像にズレが生じるのを防止可能となっている。
【００６５】
また、この実施の形態では、バックアップロール３１が変位した場合でも、当該バックアップロール３１には、位置決めピン５２によって圧接位置が一定に規制された状態で二次転写ロール３３が圧接しているため、転写ニップの形状に変化がなく、転写画像への影響はない。また、上記のごとくバックアップロール３１は、スライドフレーム８２、８３に取り付けられており、これらのスライドフレーム８２、８３は、転写ベルトフレームに対して、長穴ベアリングを介して移動自在となっているため、転写ニップの形状を変化させることなくバックアップロール３１の変位量を大きくとることができ、記録用紙３４上に転写される画像のズレをほぼゼロまで調整することができる。
【００６６】
また、二次転写ロールユニット５０、及びバックアップロールユニット５１は、ノミナルの基準位置がわかるように構成しており、ここでは偏芯カム５６、５７及び６４、６５を使用し、ユニット交換時にも簡単にノミナル状態（基準位置）に戻せるようになっている。
【００６７】
【発明の効果】
以上説明したように、この発明によれば、中間転写体を使用した画像形成装置において、転写部での画像の傾きを調整する際、従来調整しきれない部分を補い、調整幅を大きくとることができ、記録媒体の種類が異なった場合でも、常に画像の傾きを調整することが可能な転写装置を提供することができる。
【図面の簡単な説明】
【図１】 図１はこの発明の実施の形態１に係る画像形成装置の要部を示す斜視構成図である。
【図２】 図２はこの発明の実施の形態１に係る画像形成装置を示す構成図である。
【図３】 図３はこの発明の実施の形態１に係る画像形成装置を示す要部の正面構成図である。
【図４】 図４はこの発明の実施の形態１に係る画像形成装置を示す要部の正面構成図である。
【図５】 図５はこの発明の実施の形態１に係る画像形成装置の動作を示す説明図である。
【図６】 図６はバックアップロールとバックアップロールホルダーを示す斜視図である。
【図７】 図７はバックアップロールハウジングを示す斜視図である。
【図８】 図８はバックアップロールハウジングの裏面側を示す斜視図である。
【図９】 図９はバックアップロールハウジングをスライドフレームと合体させた状態を示す斜視図である。
【図１０】 図１０はバックアップロールハウジングをスライドフレームと合体させた状態を示す裏面図である。
【図１１】 図１１はこの発明の実施の形態１に係る画像形成装置の要部を示す斜視構成図である。
【図１２】 図１２はこの発明の実施の形態１に係る画像形成装置の要部を示す斜視構成図である。
【図１３】 図１３はこの発明の実施の形態１に係る画像形成装置の要部を示す構成図である。
【図１４】 図１４はスライドフレームの支持機構を示す構成図である。
【図１５】 図１５はこの発明の実施の形態１に係る画像形成装置の要部を示す側面図である。
【図１６】 図１６はこの発明の実施の形態１に係る画像形成装置の動作を示す説明図である。
【図１７】 図１７は偏芯カムの動作を示すグラフである。
【図１８】 図１８はこの発明の実施の形態１に係る画像形成装置の要部を示す側面図である。
【図１９】 図１９は偏芯カムの動作を示すテーブルである。
【図２０】 図２０は偏芯カムのイニシャライズ動作を示すフローチャートである。
【図２１】 図２１は偏芯カムを駆動するモータの駆動量を示す図表である。
【図２２】 図２２は従来の画像形成装置において二次転写される画像を示す説明図である。
【符号の説明】
３１：バックアップロール、３３：二次転写バイアスロール、５０：二次転写バイアスロールユニット、５１：バックアップロールユニット、５２：位置決めピン、５３：凹所、５４：揺動アーム、５６、５７：第１の偏芯カム（圧接幅調整手段）、６２、６３：フロント側及びリア側のフレーム、６４、６５：第２の偏芯カム、９０：ＣＰＵ。[0001]
[Technical field to which the invention belongs]
The present invention relates to an image forming apparatus that transfers a toner image onto a recording medium at a transfer portion formed by sandwiching an intermediate transfer member, and to prevent the image shift on the recording medium that occurs at the transfer portion. The present invention relates to an image forming apparatus that can be adjusted by using a new mechanism.
[0002]
[Prior art]
Conventionally, in an image forming apparatus using the above intermediate transfer member, a single color or a plurality of toner images of different colors are sequentially formed on a single or a plurality of image carriers, and a single color or A plurality of toner images of different colors are primary-transferred sequentially onto a belt-like intermediate transfer member, and then a plurality of toner images with different colors transferred onto the belt-like intermediate transfer member are recorded. It is configured to form a black and white or color image by performing secondary transfer on the medium at once and performing a fixing process.
[0003]
At that time, in the image forming apparatus using the intermediate transfer member, when a plurality of toner images having different colors transferred onto the belt-like intermediate transfer member are secondarily transferred onto the recording medium at once. In addition, the intermediate transfer member is supported by a backup roll from the inside, and the secondary transfer roll is brought into contact with the surface side of the intermediate transfer member, and a backup roll type transfer device that supplies voltage to the backup roll is adopted. ing.
[0004]
In such a transfer device of the backup roll system, one end position of the backup roll is configured to be adjustable, and one end position of the backup roll is adjusted to change the alignment of the intermediate transfer member. The inclination of the image in the secondary transfer portion as shown in FIG. 22 is adjusted. For example, Japanese Patent Application Laid-Open No. 2000-75680 discloses a technique that makes it possible to adjust the inclination of the image in the secondary transfer portion.
[0005]
[Problems to be solved by the invention]
However, the above prior art has the following problems. That is, in the case of the technique disclosed in the above Japanese Patent Application Laid-Open No. 2000-75680, one end position of the backup roll is configured to be adjustable, and one end position of the backup roll is adjusted, By changing the alignment of the transfer body, the inclination of the image in the secondary transfer portion is adjusted. For this reason, the position of the recording medium entering the secondary transfer position is regulated to an appropriate position by the registration roll that conveys the recording medium to the secondary transfer position, whereas the belt supported by the backup roll. Since the nip between the intermediate transfer member and the secondary transfer roll can only be adjusted to one end position of the backup roll, the type of recording medium differs even if the alignment of the intermediate transfer member can be adjusted. In this case, the nip state between the backup roll and the secondary transfer roll changes, and the recording medium having the higher nip pressure is conveyed in advance, and the image that is secondarily transferred to the recording medium is inclined. It had the problem that it ended up.
[0006]
The present applicant has already proposed a technique related to Japanese Patent Application No. 2001-182341 in order to solve the above-described problems. In the transfer device according to Japanese Patent Application No. 2001-182341, a toner image transferred onto an intermediate transfer member is intermediated between a back support member disposed on the back side of the intermediate transfer member and the back support member. In a transfer apparatus for transferring onto a recording medium conveyed to a transfer portion between a back side support member and a transfer member by a transfer electric field formed between the transfer member and the transfer member pressed against the surface of the transfer body, the back surface of the transfer member A pressure contact width adjusting means for adjusting a pressure contact width (biting amount) with respect to the support member is provided.
[0007]
However, in the case of the transfer device according to the above Japanese Patent Application No. 2001-182341, a pressure contact width adjusting means for adjusting the pressure contact width (biting amount) of the transfer member with respect to the back support member is provided. Since the adjustment of the pressure contact width of the transfer member is limited to a range that does not cause transfer failure, the correction range of the skew amount of the recording medium is limited to about ± 0.3 mm, and the improvement effect may not be sufficient. Has a point.
[0008]
Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to adjust the inclination of an image at a transfer portion in an image forming apparatus using an intermediate transfer member. To provide an image forming apparatus that can compensate for a portion that cannot be adjusted conventionally and can increase the adjustment range and can always adjust the inclination of an image even when the type of recording medium is different. It is in.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is directed to a back support member disposed on the back side of the intermediate transfer member, and a back support member disposed on the back side of the intermediate transfer member. By transferring the image onto a recording medium conveyed to the transfer portion between the back side support member and the transfer member by a transfer electric field formed between the transfer member and the transfer member that is pressed against the surface of the intermediate transfer member, the image is transferred. In the image forming apparatus to be formed, the positions of both end portions of the back support member are set in the direction perpendicular to the traveling direction of the intermediate transfer body with the axial center of the back support member as a fulcrum. Displacement means for displacing in the intersecting direction is provided, and the pressure contact position of the transfer member with respect to the back support member is regulated, and the transfer member is displaced so as to follow the back support member so that the shape of the transfer nip does not change. An image forming apparatus. Here, for example, a belt-like intermediate transfer member is used as the intermediate transfer member.
[0010]
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the displacement means can be automatically displaced even when the image forming apparatus is in operation.
[0018]
[Action]
In the present invention, there is provided a displacing means for displacing at least the back support member in a direction perpendicular to the advancing direction of the intermediate transfer body while maintaining the state where the intermediate transfer body is sandwiched between the back support member and the transfer member. Since it is configured, it is possible to adjust the deviation of the image transferred onto the recording medium to substantially zero without affecting the transfer performance.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
Embodiment 1
FIG. 2 is a schematic configuration diagram showing a tandem type color electrophotographic copying machine as an image forming apparatus according to Embodiment 1 of the present invention. Although this tandem type color electrophotographic copying machine is provided with an image reading device, the image forming device is not provided with an image reading device, and is based on image data output from a personal computer (not shown). Of course, a color printer, a facsimile, or the like that forms an image may be used.
[0021]
In FIG. 2, reference numeral 1 denotes a main body of a tandem type color electrophotographic copying machine. The color electrophotographic copying machine main body 1 has an image reading device (IIT) for reading an image of a document 2 at an upper portion on one end side thereof. : Image Input Terminal) 4, and inside the color electrophotographic copying machine main body 1, image data output from the image reading device 4, a personal computer (not shown) or the like, or a telephone line or a LAN The image processing apparatus (IPS: Image Processing System) 12 that performs predetermined image processing on the image data that is sent and the image output based on the image data that has been subjected to predetermined image processing by the image processing apparatus 12 An image output device (IOT: Image Output Terminal) 100 is provided. It has been.
[0022]
In the image reading device 4, an image of the original 2 pressed on the platen glass 5 by the platen cover 3 or an original conveyed automatically by an ADF (not shown) is read. The image reading device 4 illuminates a document 2 placed on a platen glass 5 with a light source 6, and reflects a reflected light image from the document 2 from a full-rate mirror 7, half-rate mirrors 8 and 9, and an imaging lens 10. The image reading element 11 composed of a CCD or the like is scanned and exposed through a reduction optical system, and the color material reflected light image of the document 2 is formed at a predetermined dot density (for example, 16 dots / mm) by the image reading element 11. It is configured to read.
[0023]
The color material reflected light image of the document 2 read by the image reading device 4 is subjected to image processing as, for example, document reflectance data of three colors of red (R), green (G), and blue (B) (8 bits each). The image processing apparatus 12 performs, for example, shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color / moving editing, etc., on the reflectance data of the document 2. Predetermined image processing is performed.
[0024]
The image data that has been subjected to the predetermined image processing by the image processing apparatus 12 as described above is a four-color document of yellow (Y), magenta (M), cyan (C), and black (K) (each 8 bits). Converted to color material gradation data (raster data), as will be described below, yellow (Y), magenta (M), cyan (C), and black (K) image forming units 13Y, 13M, 13C, 13K laser writing devices 14Y, 14M, 14C, and 14K are sent to the laser writing devices 14Y, 14M, 14C, and 14K. In these laser writing devices 14Y, 14M, 14C, and 14K, image exposure using laser light LB is performed according to the original color material gradation data of a predetermined color Is done.
[0025]
By the way, inside the tandem type color electrophotographic copying machine main body 1, as described above, four image forming units 13Y of yellow (Y), magenta (M), cyan (C), and black (K), 13M, 13C, and 13K are arranged in parallel at regular intervals in the horizontal direction.
[0026]
These four image forming units 13Y, 13M, 13C, and 13K are all configured in the same manner, and roughly divided, a photosensitive drum 15 as an image carrier that is rotationally driven at a predetermined speed along the arrow A direction. And a scorotron 16 for primary charging as a charging means for uniformly charging the surface of the photosensitive drum 15 and a laser beam corresponding to the image information of each color on the surface of the photosensitive drum 15 for scanning exposure. The image forming apparatus (image forming means) includes a laser writing device 14 that forms an electrostatic latent image, a developing device 17 that develops an electrostatic latent image formed on the photosensitive drum 15, a cleaning device 18, and the like. Yes.
[0027]
As shown in FIG. 2, the laser writing device 14 modulates the semiconductor laser 19 according to the original color material gradation data, and emits a laser beam LB from the semiconductor laser 19 according to the gradation data. The laser beam LB emitted from the semiconductor laser 19 is deflected and scanned by the rotary polygon mirror 22 via the reflection mirrors 20 and 21, and again carries an image via the reflection mirrors 20 and 21 and the plurality of reflection mirrors 23 and 24. Scanning exposure is performed on the photosensitive drum 15 as a body.
[0028]
From the image processing device 12, the laser writing devices 14Y, 14M, 14C of the image forming units 13Y, 13M, 13C, and 13K of the respective colors of yellow (Y), magenta (M), cyan (C), and black (K) are provided. The image data (raster data) of each color is sequentially output to 14K, and laser beams LB emitted according to the image data from these laser writing devices 14Y, 14M, 14C, 14K are respectively photosensitive drums 15Y, 15M, The surfaces of 15C and 15K are scanned and exposed to form an electrostatic latent image. The electrostatic latent images formed on the photosensitive drums 15Y, 15M, 15C, and 15K are respectively yellow (Y), magenta (M), and cyan (C) by the corresponding developing devices 17Y, 17M, 17C, and 17K. , And developed as a toner image of each color of black (K).
[0029]
Yellow (Y), magenta (M), cyan (C), and black (K) sequentially formed on the photosensitive drums 15Y, 15M, 15C, and 15K of the image forming units 13Y, 13M, 13C, and 13K. The unfixed toner images of the respective colors are superimposed on the surface of the intermediate transfer belt 25 at a primary transfer position where the photosensitive drums 15Y, 15M, 15C, and 15K are in contact with the intermediate transfer belt 25 as an intermediate transfer member. Sequentially transferred. Semiconductive bias rolls 26Y, 26M, 26C, and 26K as transfer members are disposed on the back side of the intermediate transfer belt 25 at the primary transfer position. These bias rolls 26Y, 26M, 26C, and 26K are disposed. Thus, the intermediate transfer belt 25 comes into contact with the surfaces of the photosensitive drums 15Y, 15M, 15C, and 15K. The primary transfer bias rolls 26Y, 26M, 26C, and 26K are applied with a voltage having a polarity opposite to the charging polarity of the toner, and the respective colors formed on the photosensitive drums 15Y, 15M, 15C, and 15K are undetermined. The contact toner images are sequentially electrostatically attracted onto the intermediate transfer belt 25 to form a full-color image.
[0030]
The intermediate transfer belt 25 includes a drive roll 27, a driven roll 28, a tension roll 29, a driven roll 30, a secondary transfer opposing roll (hereinafter referred to as “backup roll”) 31, and an idle roll. 32 is stretched with a constant tension, and is circulated and driven at a predetermined speed in the direction of arrow B by a drive roll 27 that is rotationally driven by a dedicated drive motor that is excellent in constant speed (not shown). It is like that.
[0031]
When a single color image is formed, only the desired color image forming units 13Y, 13M, 13C, and 13K are operated, and a desired single color unfixed toner image is formed on the intermediate transfer belt.
[0032]
In this way, the unfixed toner images of the respective colors of yellow (Y), magenta (M), cyan (C), and black (K) that have been primary-transferred multiple times on the intermediate transfer belt 25 are intermediate transfer belt 25. Is rotated to the secondary transfer position facing the conveyance path of the recording paper 34 (recording medium), and an unfixed toner image is transferred from the intermediate transfer belt 25 to the recording paper 34 at the secondary transfer position. Next transferred. The recording paper 34 is fed from one of the print paper trays 39, 40, 41 by a feed roller 42, conveyed to a registration roller 47 by a paper conveyance path 46 having a plurality of conveyance rollers 43, 44, and temporarily stopped. The Next, the recording paper 34 is conveyed at a predetermined timing by registration rollers 47 and is sandwiched between the secondary transfer bias roll 33 for secondary transfer and the intermediate transfer belt 25. Further, on the back side of the intermediate transfer belt 25 at the secondary transfer position, a backup roll 31 that is opposed to the secondary transfer bias roll 33 and a metal roll (not shown) that contacts the backup roll 31 are disposed. . At the secondary transfer position, by applying a voltage (normal transfer bias) having the same polarity as the toner charging polarity to the metal roll, the secondary transfer bias roll 33 forms a transfer electric field as a counter electrode, The unfixed toner image carried on the transfer belt 25 is electrostatically transferred to the recording paper 34 at the secondary transfer position. The secondary transfer bias roll 33 for secondary transfer is cleaned by a brush roll (not shown).
[0033]
Then, the recording paper 34 onto which the unfixed toner image has been transferred is peeled off from the intermediate transfer belt 25, and then sent to the fixing device 37 by the paper transport belts 35 and 36 as the two transfer material transport means, and is unfixed. The toner image is fixed and discharged onto a discharge tray 38 provided outside the apparatus main body 1. The paper transport belts 35 and 36 are composed of an endless rubber belt 35c stretched between a driving roller 35a and a driven roller 35b, and five rubber belts are stretched in parallel by one paper transport belt. ing.
[0034]
As shown in FIG. 2, the intermediate transfer belt 25 after the secondary transfer of the unfixed toner image has its residual toner removed by a belt cleaner 48 located downstream of the secondary transfer portion. .
[0035]
By the way, in the first embodiment, the toner image transferred onto the intermediate transfer member is subjected to the back support member disposed on the back side of the intermediate transfer member and the surface of the intermediate transfer member facing the back support member. In the image forming apparatus for forming an image by transferring onto a recording medium conveyed to a transfer portion between the back side support member and the transfer member by a transfer electric field formed between the transfer member and the transfer member in pressure contact with the transfer member, Displacement means for displacing at least the back support member in a direction orthogonal to the traveling direction of the intermediate transfer body is provided while maintaining the state where the intermediate transfer body is sandwiched between the back support member and the transfer member.
[0036]
In this embodiment, the displacement means can be automatically displaced even when the image forming apparatus is in operation.
[0037]
Further, in this embodiment, the amount of displacement by the displacement means is determined by a table that stores a predicted value based on the type of recording medium and the environment obtained in advance.
[0038]
Furthermore, in this embodiment, the data stored in the table can be individually corrected from the user interface.
[0039]
FIG. 3 is a schematic configuration diagram of the secondary transfer bias roll and the backup roll of the transfer apparatus according to the first embodiment of the present invention.
[0040]
As shown in FIG. 3, the secondary transfer bias roll 33 is rotatably attached to the secondary transfer bias roll unit 50, and the backup roll 31 is rotatably attached to the backup roll unit 51. The secondary transfer bias roll unit 50 and the backup roll unit 51 are provided on the secondary transfer bias roll 50 so as to engage with the positioning pin 52 provided on the backup roll unit 51 and the positioning pin 52. The recess 53 is relatively positioned.
[0041]
As shown in FIGS. 1 and 4, both ends of the secondary transfer bias roll are rotatably attached to the swing arm 54. The swing arm 54 is attached to the secondary transfer bias roll unit 50 so as to be swingable about a fulcrum 55. Further, first eccentric cams 56, 57 are disposed below the distal end portion 54 a of each swing arm 54, and the first eccentric cams 56, 57 are fixed to the rotary shaft 58. The rotating shaft 58 is rotationally driven by a driving gear 59 provided at one end thereof. An encoder 60 for detecting the reference position and the rotation amount of the first eccentric cams 56 and 57 is attached to the rotary shaft 58. Each swing arm 54 is urged by a coil spring 61 so that the tip 54 a is in pressure contact with the first eccentric cams 56 and 57. The secondary transfer bias roll 33 rotates the first eccentric cams 56 and 57 to change the angle of the swing arm 54 that is in pressure contact with the first eccentric cams 56 and 57. The horizontal movement is possible in the direction of contact with and away from the backup roll 31.
[0042]
At that time, as shown in FIG. 5, the first eccentric cams 56 and 57 are configured to have a region for moving the secondary transfer bias roll 33 in parallel with a direction in which the secondary transfer bias roll 33 contacts and separates from the backup roll 31. ing.
[0043]
On the other hand, as shown in FIG. 6, backup roll holders 80 that rotatably support the backup roll 31 are provided at both ends of the backup roll 31, and these backup holders 80 are shown in FIGS. As shown in FIG. 8, it is attached to a rectangular parallelepiped backup roll housing 81 whose lower end surface is open by screwing. Further, as shown in FIGS. 9 and 10, slide frames 62 and 63 are attached to both ends of the backup roll housing 81 to constitute a backup roll unit 51.
[0044]
As described above, the backup roll unit 51 includes the front-side slide frame 62 and the rear-side slide frame 63, as shown in FIGS. 11 and 12, and these front-side and rear-side slide frames 62, As shown in FIG. 13, 63 is attached to the transfer belt frames 82 and 83 so as to be slidable up and down. As shown in FIG. 14, a bearing 85 having a long hole 84 is attached to the transfer belt frames 82 and 83, and the long hole 84 of the bearing 85 is attached to the outer surface of the slide frames 62 and 63. The protruding pin 86 is fixed in the inserted state. The slide frames 62 and 63 are individually movable along the vertical direction on the front side and the rear side along the long hole 84 of the bearing 85. Further, as shown in FIG. 12 and the like, a pin 87 projects from the upper ends of the above-described sled frames 62 and 63, and a bearing 88 is rotatably fixed to the pin 87.
[0045]
Second eccentric cams 64 and 65 are respectively disposed on the front and rear frames 62 and 63, and the second eccentric cams 64 and 65 are fixed to the rotary shaft 66. It is attached with. As shown in FIG. 13, the rotating shaft 66 is rotatably attached to the transfer belt frames 82 and 83. The rotating shaft 66 is rotationally driven by a driving motor 69 having a driving gear 68 that meshes with the gear 67 via a gear 67 attached to the rotating shaft 66. Note that an encoder 70 for detecting the reference position and the rotation amount of the second eccentric cams 64 and 65 is attached to the rotary shaft 66. Further, the front and rear frames 62 and 63 are urged upward by a coil spring 71 attached to the upper end portion thereof, and the second eccentric cams 64 and 65 are as shown in FIG. The bearings 72 are press-contacted to bearings 72 rotatably attached to the upper outer surfaces of the front and rear frames 62 and 63. The backup roller unit 51 including the front and rear frames 62 and 63 can be moved by rotating the second eccentric cams 64 and 65 by the drive motor 69.
[0046]
At this time, the same second eccentric cams 64 and 65 are attached in / out with a phase difference of 180 degrees, and the second eccentric cams 64 and 65 are attached to the backup roll by the second eccentric cams 64 and 65, respectively. By moving the front and rear frames 62 and 63 to which the unit 51 is attached, as a result, the backup roll 31 that is rotatably attached to the backup roll unit 51 can be moved. That is, as shown in FIG. 16, the second eccentric cams 64 and 65 have both ends inclined and moved in opposite directions by the width of the long hole bearing with the backup roll 31 as a fulcrum. It is configured as follows. That is, when the out side of the backup roll 31 moves up, the in side moves down. As described above, the backup roll 31 is fixed to the slide frames 62 and 63.
[0047]
Further, as shown in FIG. 1, the secondary transfer bias roll 33, the positioning pin 52, the backup roll 31, and the rotary shaft 66 of the second eccentric cams 64 and 65 are centered at a substantially straight line L. The direction in which the secondary transfer bias roll 33 and the backup roll 31 move and the direction in which the secondary transfer bias roll unit 50 and the backup roll unit 51 move are positioned on substantially one straight line. Is configured to do.
[0048]
As shown in FIG. 16, the backup roll 31 is movable in the vertical direction about the center as a fulcrum with respect to the transfer belt frames 82 and 83 while being nipped with the secondary transfer roll 33. Thus, the shape of the transfer nip is not changed.
[0049]
Furthermore, in the above embodiment, as shown in FIG. 20, the rotation amount of the drive motor 69 is controlled by the CPU 90 in accordance with the type of recording medium, environment such as temperature and humidity. Further, the CPU 90 is configured to appropriately set the control amount based on storage means such as NVM in which a correction table is stored in advance.
[0050]
Further, in this embodiment, if the walk of the intermediate transfer belt 25 becomes a problem by displacing the backup roll 31, if necessary, on the downstream side of the transfer unit and the upstream side of the image forming position. The roll 32 and the like arranged in the above may be configured to be displaceable in the direction opposite to the displacement direction of the backup roll 31.
[0051]
With the above configuration, in the image forming apparatus according to this embodiment, when adjusting the inclination of the image at the transfer portion in the image forming apparatus using the intermediate transfer member as follows, it cannot be adjusted conventionally. The portion can be compensated for and the adjustment range can be increased, and the inclination of the image can always be adjusted even when the type of the recording medium is different.
[0052]
That is, in the image forming apparatus provided with the transfer device according to this embodiment, as shown in FIGS. 1 and 3 to 14, the positions of both ends of the backup roll 31 are controlled by the rotation amount of the drive motor 69. Accordingly, the secondary transfer roll 33 that is adjustable as shown in FIG. 14 and press-contacted with the backup roll 31 in a state in which the position is regulated by the pin 52 also follows the backup roll 31. It has become.
[0053]
As shown in FIG. 17, the profiles of the second eccentric cams 64 and 65 that are rotationally driven by the drive motor 69 can operate ± XX mm with reference to zero on the layout. The width of the long-hole bearing 86 that permits the movement of is also set accordingly.
[0054]
By the way, when the toner image transferred onto the intermediate transfer belt 25 is secondarily transferred onto the recording paper 34, the power of the image forming apparatus is first turned on before the operation for correcting the deviation such as the skew of the image. In this case, an initialization operation is performed to hold the eccentric cams 64 and 65 at the zero point.
[0055]
In this initialization operation, immediately after the image forming apparatus is turned on, it is impossible to know how many positions the drive motor 69 is currently holding. For this reason, the operation for initializing the holding position of the drive motor after the customer mode is entered after turning on the power and after the belt module is inserted / removed is the cam initialization operation.
[0056]
The shapes of the eccentric cams 64 and 65 are as shown in FIG. 18 and are connected to the drive motor 69. The positions of the eccentric cams 64 and 65 are expressed by the number of steps of the drive motor 69 with respect to the reference position of the cam. As shown in FIG. 18, the CW direction is indicated by + and the CCW direction is indicated by − when viewed from the mounting surface of the drive motor 69.
[0057]
1. 3. If an actuator exists between the slits of the cam home sensor (hereinafter referred to as ON), rotate the drive motor in the CCW direction. Proceed to the operation. If there is no actuator (hereinafter referred to as OFF), rotate the drive motor in the CW direction. Proceed to
2. If the cam home sensor changes from OFF to ON, the drive motor is stopped. If the cam home sensor does not turn from OFF to ON even after the predetermined time shown in FIG. 19, the drive motor 69 is stopped and a cam home sensor abnormality is notified to the user interface.
3. Next, the drive motor 69 is rotated in the CCW direction.
4). When the cam home sensor is turned from ON to OFF, the drive motor is further rotated in the CCW direction by Sc step from there, and stopped and held. If the cam home sensor does not turn from ON to OFF even after Tc seconds, the drive motor is stopped and a cam home sensor abnormality is notified.
5. Here, the drive pulse of the drive motor is Fc (pps).
[0058]
FIG. 20 is a flowchart showing the initialization operation of the eccentric cam.
[0059]
Next, prior to the image forming operation, the parallelism adjusting operation of the backup roll 31 is executed.
1. The operable range is ± 200 steps after cam initialization, and the positioning pins 52 of the secondary transfer roll 33 are displaced by 0.02 mm in 8 steps.
2. Further, as shown in FIG. 21, the parallelism adjustment data is the sum of the paper basis, paper size, plain paper / coated paper data, and a function with humidity as a variable, and the rotation step of the drive motor. A table for determining the number is stored in advance in the NVM for adjustment. In FIG. 21, the paper data are all “0”, but actually, the value of the paper data obtained by the experiment is filled. The function is shown in Equation 1 below, where x is humidity, A is a constant, and has a humidity coefficient NVM.
[0060]
[Expression 1]

[0061]
That is, the adjusted NVM value is then given by equation (2).
Numbers are rounded off to the nearest whole number.
Further, when an abnormality of the humidity sensor occurs, A = 0 is set.
[0062]
[Expression 2]

[0063]
3. In addition, the sales engineer 2. It is possible to change the adjusted NVM value. That is, the value of (paper basis weight, paper size, data for each plain paper / coated paper) and A can be changed.
4). Further, an offset NVM that can be input by the sales engineer from the special mode is provided, which makes it possible to offset the entire adjustment NVM by a certain amount. In the parallelism adjustment operation, the total value of offset NVM + adjustment NVM does not always exceed ± 200 steps.
5. Further, each tray containing the recording paper 34 is provided with a tray offset NVM that can be input by the service engineer from the special mode, and fine adjustment is possible with respect to the value of the selected offset NVM + adjustment NVM. Note that the total value of tray offset NVM + offset NVM + adjustment NVM does not exceed ± 200 steps.
6). The humidity sampling interval is set to about 5 minutes.
7). In addition, the time when the humidity sampling results are reflected is set to be implemented as early as possible.
8). Furthermore, the reflection timing of various paper information is completed before the secondary transfer is executed even when the image forming apparatus is in operation.
[0064]
As described above, in the image forming apparatus according to the present embodiment, when the paper or environment changes, the data is read from the table stored in the adjustment NVM or the like even during the copy job, and the drive motor 69 is read. By controlling the rotation amount, the amount of displacement of the backup roll 31 in the direction orthogonal to the moving direction of the intermediate transfer belt 25 is adjusted, and the toner image transferred from the intermediate transfer belt 25 onto the recording paper 34 is shifted. Can be prevented.
[0065]
In this embodiment, even when the backup roll 31 is displaced, the secondary transfer roll 33 is in pressure contact with the backup roll 31 in a state where the pressure contact position is regulated to be constant by the positioning pin 52. There is no change in the shape of the transfer nip, and there is no effect on the transferred image. Further, as described above, the backup roll 31 is attached to the slide frames 82 and 83, and these slide frames 82 and 83 are movable with respect to the transfer belt frame via long hole bearings. The displacement amount of the backup roll 31 can be increased without changing the shape of the transfer nip, and the deviation of the image transferred onto the recording paper 34 can be adjusted to almost zero.
[0066]
Further, the secondary transfer roll unit 50 and the backup roll unit 51 are configured so that the nominal reference position can be understood. Here, the eccentric cams 56, 57 and 64, 65 are used, so that the unit can be easily replaced. It is possible to return to the nominal state (reference position).
[0067]
【The invention's effect】
As described above, according to the present invention, in the image forming apparatus using the intermediate transfer member, when adjusting the inclination of the image at the transfer portion, the portion that cannot be adjusted conventionally is compensated and the adjustment range is increased. Therefore, it is possible to provide a transfer device that can always adjust the inclination of an image even when the types of recording media are different.
[Brief description of the drawings]
FIG. 1 is a perspective configuration diagram showing a main part of an image forming apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram showing an image forming apparatus according to Embodiment 1 of the present invention.
FIG. 3 is a front structural view of a main part showing an image forming apparatus according to Embodiment 1 of the present invention.
FIG. 4 is a front structural view of the main part showing the image forming apparatus according to Embodiment 1 of the present invention.
FIG. 5 is an explanatory view showing the operation of the image forming apparatus according to Embodiment 1 of the present invention.
FIG. 6 is a perspective view showing a backup roll and a backup roll holder.
FIG. 7 is a perspective view showing a backup roll housing.
FIG. 8 is a perspective view showing the back side of the backup roll housing.
FIG. 9 is a perspective view showing a state in which the backup roll housing is united with the slide frame.
FIG. 10 is a back view showing a state in which the backup roll housing is united with the slide frame.
FIG. 11 is a perspective configuration diagram showing the main part of the image forming apparatus according to Embodiment 1 of the present invention.
FIG. 12 is a perspective configuration diagram showing the main part of the image forming apparatus according to Embodiment 1 of the present invention.
FIG. 13 is a block diagram showing a main part of the image forming apparatus according to Embodiment 1 of the present invention.
FIG. 14 is a configuration diagram showing a support mechanism of the slide frame.
FIG. 15 is a side view showing the main part of the image forming apparatus according to Embodiment 1 of the present invention.
FIG. 16 is an explanatory view showing the operation of the image forming apparatus according to Embodiment 1 of the present invention.
FIG. 17 is a graph showing the operation of the eccentric cam.
FIG. 18 is a side view showing the main part of the image forming apparatus according to Embodiment 1 of the present invention.
FIG. 19 is a table showing the operation of the eccentric cam.
FIG. 20 is a flowchart showing an initialization operation of the eccentric cam.
FIG. 21 is a chart showing the drive amount of the motor that drives the eccentric cam.
FIG. 22 is an explanatory view showing an image secondarily transferred in a conventional image forming apparatus.
[Explanation of symbols]
31: Backup roll, 33: Secondary transfer bias roll, 50: Secondary transfer bias roll unit, 51: Backup roll unit, 52: Positioning pin, 53: Recess, 54: Swing arm, 56, 57: First Eccentric cams (pressure contact width adjusting means), 62, 63: front and rear frames, 64, 65: second eccentric cam, 90: CPU.

Claims (2)

A toner image transferred onto the intermediate transfer member, and a back support member disposed on the back side of the intermediate transfer member;
Transfer is performed on a recording medium conveyed to a transfer portion between the back-side support member and the transfer member by a transfer electric field formed between the transfer member that faces the back-side support member and presses against the surface of the intermediate transfer member. In the image forming apparatus for forming an image,
Displacement for displacing the positions of both ends of the back support member in a direction perpendicular to the advancing direction of the intermediate transfer member and a direction intersecting the surface of the intermediate transfer member, with the axial center of the back support member as a fulcrum An image forming apparatus, characterized in that the transfer member is displaced in such a manner that the position of the pressure contact with the back support member is regulated and the shape of the transfer nip does not change following the back support member.   The image forming apparatus according to claim 1, wherein the displacing unit can be automatically displaced even when the image forming apparatus is in operation.

Images