CN101430528A - Image forming apparatus - Google Patents

Abstract

An image forming apparatus includes first and second image bearing members on which a toner images are to be formed; a conveying member onto which the toner images are to be transferred; a conveying member position index detecting device for detecting a conveying member position index provided on the conveying member along the movement direction of the conveying member; an image bearing member position index detecting device for detecting the image bearing member position indices provided on the second image bearing member along a rotational direction of the second image bearing member; an adjusting device for adjusting a rotational speed of the second image bearing member; a controller for controlling the adjusting device so as to adjust a position of an image bearing member position index correspondingly to the conveying member position index, on the basis of detection results of the conveying member position index detecting device and the image bearing member position index detecting device; and an initializing portion for performing an initializing operation of the adjusting device when an amount of deviation between the conveying member position index and the corresponding image bearing member position index is out of a predetermined range.

Description

Imaging device

Technical field

The present invention relates to by with the second color toner image overlay on the first color toner image to form the imaging device of colo(u)r-mixture diagram picture.Particularly, the present invention relates to improve the control of overlapping accuracy between the first color toner image and the second color toner image.

Background technology

By coming into operation with the tandem type imaging device that forms full-colour image at image bearing member different aspect the development color (photosensitive drums, sensitization band etc.) along transfer member (intermediate transfer belt, recording materials conveying belt etc.) layout is a plurality of.In the tandem type imaging device, toner image forms by a plurality of image bearing members parallel but that have a different timing and with the overlap mode transfer printing, makes the sheet material enormous amount of carrying out imaging.Therefore, might realize high productivity.

Yet, in the tandem type imaging device, because the departure that toner image forms between the toner image that timing error causes in a plurality of image bearing members increases easily, make that in some cases aberration or irregular colour are at the trickle part place of high resolving power full-colour image clearly.

Japanese Laid-Open Patent Application (JP-A) Sho 64-6981 discloses a kind of imaging device, wherein, on intermediate transfer belt, detect and be transferred to the toner image that is used to control (register mark) of intermediate transfer belt, and the exposure of regulating each photosensitive drums begins regularly from a plurality of photosensitive drums.Each toner image that is used to control forms cruciform, and this cruciform forms by making straight line relevant with the intermediate transfer direction of belt travel and the straight line relevant with the Width of intermediate transfer belt intersect each other to meet at right angles.Then, testing result based on the Width line, regulate the electrostatic image relevant and write beginning regularly with the sense of rotation of image bearing member, and based on the testing result of moving direction line, the electrostatic image of regulating for the turning axle direction of image bearing member is write beginning regularly.

JP-A Hei 5-241457 discloses a kind of imaging device, wherein, be transferred to the toner image that is used to control (register mark) on the intermediate transfer belt detecting on the intermediate transfer belt, begin regularly so that regulate the exposure of downstream photosensitive drums from the upstream side photosensitive drums.Arrive the timing of the secondary transfer printing portion of downstream photosensitive drums at the front end that is transferred to the first color toner image on the intermediate transfer belt, the downstream photosensitive drums is rotated half substantially around its turning axle, makes the front end of the second color toner image on the photosensitive drums of downstream arrive secondary transfer printing portion.

JP-A 2004-145077 discloses a kind of structure, wherein, position mark writes on each Electrifier frame, photoreceptor and the intermediate transfer member, and it is detected so that the velocity contrast between detection Electrifier frame, photoreceptor and the intermediate transfer member, subsequently according to this velocity contrast information, proofread and correct image on the Electrifier frame, photoreceptor and the deviation between the image on the intermediate transfer belt.In addition, for correcting action, a kind of structure that is used to change the rotational speed of Electrifier frame, photoreceptor has been described.

In the tandem type imaging device, when having velocity contrast between middle transfer member and the image bearing member, produced the second color toner image that is formed on second image bearing member with respect to the aliasing error that is transferred to the first color toner image on the intermediate transfer member from first image bearing member.The second color toner image is one of toner image of second color, the 3rd color, the 4th color, the 5th color etc., and the toner image of these colors will be positioned on the first color toner image that at first is transferred on the intermediate transfer member or the top.

In JP-A Sho 64-6981 and JP-A Hei 5-241457, phototiming can be regulated so that first color toner image that elimination had produced and the aliasing error between the second color toner image before beginning to write electrostatic image, yet, arrive the first color toner image that produced during the transfer printing portion and the aliasing error the second color toner image can not be eliminated to toner image from beginning to write electrostatic image.

The control of describing among the JP-A Sho 64-6981 can not be eliminated at the toner image that is used to control by detection and regulate the first color toner image that electrostatic image writing on first image bearing member produced after the beginning regularly and the aliasing error between the second color toner image.

The control of describing among the JP-A Hei 5-241457 can be eliminated from the toner image that is used to control that is formed on first image bearing member and be transferred to the aliasing error that has resulted from the intermediate transfer member between the first color toner image and the second color toner image in the first transfer printing portion during the toner image that is used to control that is transferred is detected.Yet this control can not be eliminated and regulate electrostatic image from the toner image that is used to control by detection and regularly resulted from aliasing error between the first color toner image and the second color toner image in the beginning write on second image bearing member during the first color toner image and the second color toner image arrive secondary transfer printing portion.

Therefore, JP-A Sho 64-6981 and JP-A Hei 5-241457 can not solve because of equaling or be shorter than the first color toner image that rotation inequality in time of image bearing member swing circle or velocity perturbation cause and the aliasing error between the second color toner image.

Yet, with regard to image bearing member, always produce the short time velocity perturbation that excentricity or load change because of image bearing member cause, with regard to intermediate transfer member, always produce variation in thickness and the excentricity of driven roller or the short time velocity perturbation that load change causes, and fluctuating range is greater than the fluctuating range in the image bearing member situation because of intermediate transfer member.In addition, the velocity perturbation of image bearing member and the velocity perturbation of intermediate transfer member periodically provide opposite phase (the leading and phase delay of phase place), make periodically to produce obvious velocity contrast.

In other words, if use the large scale imaging device, wherein, by using the amplitude that image bearing member that diameter and weight increases and driven roller suppress velocity perturbation and the cycle of extending speed fluctuation, then the control of describing among control of describing among the JP-A Sho 64-6981 and the JP-A Hei 5-241457 can effectively be worked.

Yet, when hope is reduced to the picture equipment size by the image bearing member that uses diameter and weight and reduce and driven roller, for image bearing member and driven roller, all be easy to produce the short period velocity perturbation, make the aliasing error of winning between the toner image and second toner image unacceptable.

When experimentizing, find that this aliasing error is issued to the level that is equivalent to 5 sweep traces (200 μ m) at worst condition by the test model that uses size to reduce.

Under the situation of the disclosed structure of JP-A 2004-145077, detect and proofread and correct near the position deviation information of transfer printing portion, thereby can address the above problem.Yet in the disclosed structure of JP-A 2004-145077, change has taken place in the speed of Electrifier frame, photoreceptor when having prevented position deviation, makes can cause following point in some cases.When the speed that changes Electrifier frame, photoreceptor during with the correction position deviation, the interval when changing between position mark and the image for sub scanning direction also changes.For example, under the situation that the speed of Electrifier frame, photoreceptor increases, described interval increases, and under the situation that the speed of Electrifier frame, photoreceptor reduces, described interval reduces.Therefore, the offset correction operation of having carried out might cause adverse effect to follow-up offset correction operation.Therefore find, when Electrifier frame, photoreceptor speed increases and Electrifier frame, photoreceptor speed can not have problems when reducing to take place at random, but correcting value just increases and the maximal value of setover correcting value in some cases continuously, thereby causes might failing aspect the abundant correction control.

Summary of the invention

Fundamental purpose of the present invention provides a kind of imaging device, wherein, has realized stable correction control, even after each image bearing member and the velocity perturbation of intermediate transfer member generation short-term, and also can be toner image is accurately overlapping in transfer printing portion.

According to an aspect of the present invention, provide a kind of imaging device, having comprised:

First image bearing member will form toner image on it;

Second image bearing member will form toner image on it;

Transfer member is in order to carrying and conveying toner image;

First transfer device is in order to be transferred to the toner image on first image bearing member on the transfer member at first transfer printing portion place;

Second transfer device, in order to the toner image on second image bearing member is transferred on the transfer member at second transfer printing portion place, the described second transfer printing portion is positioned at the downstream of the first transfer printing portion with respect to the moving direction of transfer member;

The transfer member position mark, its moving direction along transfer member is arranged on the transfer member;

The image bearing member position mark, its sense of rotation along second image bearing member is arranged on second image bearing member;

Transfer member position mark pick-up unit is in order to detect the transfer member position mark;

Image bearing member position mark pick-up unit is in order to detected image bearing carrier position mark;

Regulating device is in order to the rotational speed of regulating second image bearing member or second image bearing member position with respect to the transfer member moving direction;

Controller, in order to the regulating and controlling device, so that according to the testing result of transfer member position mark pick-up unit and image bearing member position mark pick-up unit, regulate the position of image bearing member position mark corresponding to the transfer member position mark that will arrive the second transfer printing portion; With

Initialization section when surpassing predetermined value with absolute value representation in order to the departure between transfer member position mark and corresponding image bearing member position mark, is carried out the initialization operation of regulating device.

After considering below in conjunction with the accompanying drawing description of the preferred embodiment of the present invention, these and other purpose of the present invention, feature and advantage will become apparent.

Description of drawings

Fig. 1 is the synoptic diagram of structure that shows the imaging device of first embodiment.

Fig. 2 is the synoptic diagram that shows the structure of first transfer printing portion and secondary transfer printing portion.

Fig. 3 is the synoptic diagram of the imaging device of embodiment 1.

Fig. 4 shows the synoptic diagram that is formed on the primary importance mark on first image bearing member.

Fig. 5 shows the synoptic diagram that is formed on the transfer member position mark on the transfer member.

Fig. 6 shows the synoptic diagram that is formed on the second place mark on second image bearing member.

Fig. 7 is the synoptic diagram that shows the used structure of control among the embodiment 1.

Fig. 8 is the block diagram of the control summary among the embodiment 1.

Fig. 9 is the control flow chart among the embodiment 1.

Figure 10-14 is respectively the process flow diagram of the control of task 1-5.

Figure 15 is the synoptic diagram that shows the exposure control among the embodiment 2.

Figure 16 is the synoptic diagram that shows the angle index reader.

Figure 17 is the synoptic diagram that shows the inclination control of the photosensitive drums among the embodiment 3.

Figure 18-20 is respectively side view, front view and the planimetric map of the tilt adjusting mechanism of photosensitive drums.

Figure 21 is the synoptic diagram that shows the used structure of control among the embodiment 4.

Figure 22 is the block diagram of the control summary among the embodiment 4.

Figure 23 is the synoptic diagram of structure that shows the imaging device of embodiment 6.

Figure 24 is the synoptic diagram that shows the used structure of control among the embodiment 7.

Figure 25 shows to detect the synoptic diagram of photosensitive drums along the amount of movement of the axial direction of this photosensitive drums.

Figure 26 shows the synoptic diagram that is formed on the first width position mark on first image bearing member.

Figure 27 shows the synoptic diagram that is formed on the transfer member width position mark on the transfer member.

Figure 28 shows the synoptic diagram that is formed on the second width position mark on second image bearing member.

Figure 29 is the synoptic diagram that shows distance between the first width position mark and the transfer member width position mark.

Figure 30 is the synoptic diagram that shows distance between the transfer member width position mark and the second width position mark.

Figure 31 is the synoptic diagram that shows the used structure of control among the embodiment 8.

Figure 32 is the synoptic diagram that shows the used second image bearing member travel mechanism of control among the embodiment 9.

Figure 33 (a) and 33 (b) show the synoptic diagram that is carried on the image correspondence on the transfer member and second image bearing member respectively.

Figure 34 shows the figure that concerns between the controlled quentity controlled variable of the velocity perturbation of transfer member and second image bearing member.

Figure 35 is the figure that is presented at the controlled quentity controlled variable vibration under the controlled situation of rotational speed of second image bearing member.

Figure 36 is the synoptic diagram that shows the used second image bearing member travel mechanism of control among the embodiment 10.

Figure 37 is the time diagram of the control among the embodiment 10.

Figure 38 is the process flow diagram of the control among the embodiment 10.

Figure 39 is the process flow diagram of another control among the embodiment 10.

Figure 40 is the synoptic diagram that shows the structure of the pinkish red image forming portion among the embodiment 11.

Figure 41 shows the figure that exposure device is fixed to the effect on the Electrifier frame, photoreceptor supporting member.

Figure 42 is the synoptic diagram that shows the structure of the pinkish red image forming portion among the embodiment 12.

Figure 43 is the synoptic diagram that shows the used structure of control among the embodiment 5.

Figure 44 is the process flow diagram that shows the control summary among the embodiment 5.

Figure 45 is the synoptic diagram that shows the control summary among the embodiment 5.

Figure 46 (a) and 46 (b) are the synoptic diagram of the summary of the drive motor control section in the displayed map 5.

Figure 47 is the synoptic diagram of structure that shows the imaging device of second embodiment.

Figure 48 is the synoptic diagram of structure that shows the imaging device of the 3rd embodiment.

Figure 49 is the synoptic diagram that shows the used structure of control among the embodiment 13.

Embodiment

Hereinafter, embodiments of the present invention is described in detail with reference to the accompanying drawings.The present invention also is applicable to other embodiment, wherein, part or all structure of each embodiment is replaced by optional structure, as long as second toner image of first toner image that forms and formation moves each other each other along the moving direction that is provided with overlap mode.

Therefore, the present invention implements in the imaging device of transfer member between not only can be in use, also can implement in the imaging device that toner image is transferred on the recording materials that are carried on the recording materials transfer member.In addition, also possible is, the present invention not only can be at the tandem type imaging device (wherein, a plurality of image bearing members are arranged along intermediate transfer member or recording materials transfer member) middle enforcement, also can implement at single-drum formula imaging device (being used on the single image bearing carrier, forming the toner image of multiple color).

In the present embodiment, only describe the major part relevant, but by increasing necessary device, equipment and shell mechanism, the present invention can implement in multiple use with the formation/transfer printing of toner image, for example, printer, various printing machine, duplicating machine, facsimile recorder and Multi Role Aircraft.

Incidentally, will omit explanation and unnecessary explanation below to the general content of imaging device described in JP-A Sho 64-6981 and the JP-A Hei5-241457.In the following description, for the purpose of understanding the present invention, the composition member described in the claim only shows in bracket, therefore, should be appreciated that these members are not limited to corresponding particular elements shown in reference number among each embodiment or the symbol etc.

In each embodiment, primary importance mark 221, second place mark 222 and transfer member position mark 223 in some cases pattern form, form aspect position, material, the recording/reproducing method different, but these position marks are represented by identical reference number and are dispensed unnecessary explanation.

Similarly, writing station 31Y with 34 with reader (reading device) 32Y, 32M, 32C, 32K, 35Y, 35M, 35C and 35K detect aspect the composition different, but these devices are represented by identical reference symbol and are dispensed unnecessary explanation.

＜the first embodiment 〉

Fig. 1 is the synoptic diagram of composition that shows the imaging device of first embodiment, and Fig. 2 is the synoptic diagram that shows the composition of first transfer printing portion and secondary transfer printing portion.

As shown in Figure 1, the imaging device 100 of first embodiment is panchromatic laser beam printers, and wherein, the imaging station PY, PM, PC and the PK that are used for yellow, cyan, magenta and black arrange along intermediate transfer belt 9.

At PY place, imaging station, yellow toner image is formed on photosensitive drums 1Y (first image bearing member) and upward and by photosensitive drums 1Y carries and conveying, subsequently, at the first transfer printing portion TY place, yellow toner image is transferred on the intermediate transfer belt (transfer member) 9 for the first time by the first transfer device 5Y.At PM place, imaging station, pinkish red toner image is formed on photosensitive drums 1M (second image bearing member) and upward and by photosensitive drums 1M carries and conveying, subsequently, at the second transfer printing portion TM place, pinkish red toner image is transferred on the intermediate transfer belt 9 for the first time by the second transfer device 5M.Second TM of transfer printing portion is positioned at the downstream of first TY of transfer printing portion with respect to the moving direction of intermediate transfer member (transfer member).At imaging station PC and PK place, cyan toner image and black toner image are respectively formed on photosensitive drums 1C and the photosensitive drums 1K, and are transferred to similarly on the intermediate transfer belt 9 with overlap mode.

Intermediate transfer belt 9 as the transfer member example supports around driven roller 13, jockey pulley 12 and backing roll 10 extensions and by them, and rotates along direction shown in the arrow R2.

Four kinds of color toner images that are carried on the intermediate transfer belt 9 are transported to the T2 of secondary transfer printing portion, at this place, these toner images by secondary transfer printing jointly to recording materials P.Recording materials P is taken out from sheet feeding box 20 by sheet feeding roller 14, and is separated to be fed into registration roller 16 one by one by tripping device 15.

Registration roller 16 is fed into the T2 of secondary transfer printing portion with recording materials P, makes the front end of recording materials P overlap with toner image on the intermediate transfer belt 9.

Secondary transfer printing has four kinds of color toner record images material P to be transported to fixing device 17 and to carry out hot pressing on it, makes the full-colour image photographic fixing to the surface of recording materials P.

Intermediate transfer belt cleaning device 18 is removed through the secondary transfer printing T2 of portion and is remained in transfer printing residual toner on the intermediate transfer belt 9.

Except being arranged at the used toner color of developing apparatus 4Y, 4M, 4C and 4K in the imaging station for outside yellow, pinkish red, cyan and the black (that is, differing from one another), imaging station PY, PM, PC and PK constitute each other similarly.

Therefore, hereinafter, only describe and be used for yellow imaging station PY, the composition member that should be appreciated that other imaging stations PM, PC and PK replaces with C, M by the suffix Y with the reference number of relevant components member and K carries out unified description.

As shown in Figure 2, at PY place, imaging station, charging device 2Y, exposure device 3Y, developing apparatus 4Y, first transfer roll 5Y and cleaning device 6Y arrange around photosensitive drums 1Y.

Be applied to by organic photoconductor (OPC) layer that will have negative charge polarity as the photosensitive drums 1Y of the first image bearing member example and constitute on the outer surface of aluminum barrel and rotate along direction shown in the arrow R1.

Charged particle is transmitted on the surface of photosensitive drums 1Y by the negative voltage of being supplied with by power supply D3, charging device 2Y charges to uniform negative potential for photosensitive drums 1Y.

The exposure device 3Y that forms the device example as the first static picture utilizes laser beam by rotating mirror the surface of photosensitive drums 1Y to be scanned, and described laser beam obtains by the sweep trace view data that is formed by color separation yellow color component image decompressor being carried out the ON-OFF modulation.By this scanning, electrostatic image writes on the surface of (being formed on) charged photosensitive drums 1Y with the resolution of 600dpi (point/inch).

Developing apparatus 4Y as the first developing apparatus example comprises the two-component developing agent of toner and magnetic carrier potpourri and toner is charged to negative polarity by stirring.Charged toner is carried on the development sleeve 4s with upright chain state, and described development sleeve rotates along the direction opposite with photosensitive drums 1Y sense of rotation around fixed magnetic pole 4j, thus friction photosensitive drums 1Y.

Power supply D4 applies developing voltage (form is the negative dc voltage with AC bias) for development sleeve 4s, make toner be deposited on the electrostatic image on the photosensitive drums 1Y, photosensitive drums 1Y for development sleeve 4s for positive polarity so that electrostatic image is oppositely developed.

First transfer roll 5Y is clipped in intermediate transfer belt 9 between first transfer roll 5Y and the photosensitive drums 1Y, with formation first transfer printing TY of portion as the first transfer printing portion example between photosensitive drums 1Y and intermediate transfer belt 9.

Power supply DY applies positive direct-current voltages for first transfer roll 5, is transferred to through on the intermediate transfer belt 9 of the first transfer printing TY of portion with the electronegative toner that will be carried on the photosensitive drums 1Y.

Cleaning device 6 utilizes cleaning doctor friction photosensitive drums 1Y, to remove the lip-deep transfer printing residual toner that passes through the first transfer printing TY of portion and remain in photosensitive drums 1Y.

Secondary transfer roller 11 is pressed against intermediate transfer belt 9 on the backing roll 10, to form the T2 of secondary transfer printing portion between intermediate transfer belt 9 and secondary transfer roller 11.

At secondary transfer printing portion T2 place, recording materials P with intermediate transfer belt 9 on the overlapping mode of toner image clamp, carry and process through the secondary transfer printing T2 of portion in, toner image from middle transfer belt 9 secondary transfer printings to recording materials P.

Power supply D2 applies positive direct-current voltages for secondary transfer roller 11, so that the transfer printing electric current flows through the series circuit that is formed by backing roll 10, intermediate transfer belt 9, recording materials P and secondary transfer roller 11.Part transfer printing electric current flows through the toner covering part of intermediate transfer belt 9, to participate in toner moving from middle transfer belt 9 to recording materials P.

＜embodiment 1 〉

Fig. 3 is the fragmentary, perspective view of the imaging device of embodiment 1, Fig. 4 shows the synoptic diagram that is formed on the primary importance mark on first image bearing member, Fig. 5 shows the synoptic diagram that is formed on the transfer member position mark on the transfer member, and Fig. 6 shows the synoptic diagram that is formed on the second place mark on second image bearing member.

Fig. 7 is the synoptic diagram of the used structure of control in the displayed map 1, and Fig. 8 is the block diagram that shows the control summary among the embodiment 1, and Fig. 9 is the process flow diagram of control among the embodiment 1, and Figure 10-14 is respectively the process flow diagram of the control of task 1-5.

As shown in Figure 3, in embodiment 1, (1C is on inside surface 1K) for 1Y, 1M at image bearing member to be used for position mark (221) magnetic recording of each sweep trace.Synchronous with the primary importance mark (221) of image bearing member (1Y), the transfer member position mark (251) that is used for each sweep trace locates to be formed on transfer member (9) side in the first transfer printing portion (TY).Then, regulate second image bearing member (1M, 1C, rotational speed 1K).Therefore, (1K) (TM, TC TK) locate to overlap on the transfer member position mark (251) that is formed on the intermediate transfer belt 9 Cheng Zai image bearing member position mark (222) in the second transfer printing portion for 1M, 1C by second image bearing member.

Photosensitive drums 1Y is driven by drive motor MY, thereby with constant rotational speed rotation substantially, and intermediate transfer belt 9 drives by drive motor M9, thereby with constant rotational speed rotation substantially.

As the photosensitive drums 1M of the second image bearing member example, 1C and 1K are respectively by drive motor MM, and MC and MK drive, thereby with constant rotational speed rotation substantially, but and its rotational speed independent regulation.These drive motor play the effect of regulating device when the correction position deviation.

On surface as the photosensitive drums 1Y of the first image bearing member example, exposure device (3Y: Fig. 2) write the sweep trace that is used for electrostatic image with the spacing of 42 μ m (600dpi) along the sense of rotation of photosensitive drums 1Y.

As shown in Figure 4, magnetic recording layer EY is formed on the inside surface of photosensitive drums 1Y, and as shown in Figure 3, writing station 31Y correspondingly is arranged in the writing position of sweep trace.Concerning each time sweep trace being write photosensitive drums 1Y goes up, writing station 31Y with primary importance mark magnetic recording in magnetic recording layer EY.

The single long beginning label 211 at preset distance place is by magnetic recording before first image-region of yellow, and three long end marks 231 correspondingly are arranged in the rear end of first image-region.That is to say,, be provided with the image bearing member position mark corresponding with image with regard to the turning axle direction of image bearing member, being positioned at image-region zone in addition.These image bearing member position marks are along the sense of rotation setting of image bearing member.Zone be positioned at the exterior lateral area downstream with regard to the sense of rotation of image bearing member is provided with beginning label.With regard to the sense of rotation of image bearing member, being positioned at the exterior lateral area upstream region, end mark is set.

As shown in Figure 5, on the inside surface of intermediate transfer belt 9, form magnetic recording layer E9.As shown in Figure 3, with inner side as the corresponding intermediate transfer belt 9 of reader 32Y of the first transfer member position mark pick-up unit example, arrange writing station 34.Read primary importance mark 221 each time for reader 32Y, writing station 34 with transfer member position mark 251 magnetic recordings in the magnetic recording layer E9 of intermediate transfer belt 9.

The single long beginning label 241 at preset distance place is by magnetic recording before first image-region of yellow, and three long end marks 261 correspondingly are arranged in the rear end of first image-region.

As shown in Figure 6, magnetic recording layer EM, EC and EK are formed on photosensitive drums 1M, on the inside surface of 1C and 1K, writing station 31M, 31C and 31K correspondingly are arranged in the writing position of respective scan line.For each time sweep trace being write on photosensitive drums 31M, 31C and 31K go up, writing station 31M, 31C and 31K with second place mark 222 magnetic recordings at magnetic recording layer EM, among EC and the EK.On photosensitive drums 1M (second image bearing member), image bearing member position mark 222 is along the sense of rotation setting of second image bearing member.This also is like this concerning other photosensitive drums.

In magenta, the single long beginning label 212 at preset distance place is by magnetic recording before second image-region of cyan or black, and three long end marks 232 correspondingly are arranged in the rear end of second image-region.

By at photosensitive drums 1Y, the position beyond the 1M, the image-region of 1C and 1K for example applies that the information recording carrier of magnetic material can form magnetic recording layer EY, EM, EC and EK satisfactorily.Except photosensitive drums 1Y, 1M, beyond the inside surface of 1C and 1K, described position can also be to be positioned at the non-image formation part that outside surface end, detection end face etc. are located.

(TK: Fig. 1), reader 32M, 32C and 32K and reader 35M, 35C and 35K arrange respectively in pairs for TM, TC in the first transfer printing portion as the second transfer printing portion example.

When reader 35M (transfer member position mark pick-up unit) reads transfer member position mark 251, reader 32M (image bearing member position mark pick-up unit) is when reading second place mark simultaneously, and the sweep trace that is formed on the photosensitive drums 1M overlaps on the sweep trace that is carried on the intermediate transfer belt 9.

When reader 25C reads transfer member position mark 251, when reader 32C read second place mark simultaneously, the sweep trace that is formed on the photosensitive drums 1C overlapped on the sweep trace that is carried on the intermediate transfer belt 9.

When reader 25K reads transfer member position mark 251, when reader 32K read second place mark simultaneously, the sweep trace that is formed on the photosensitive drums 1K overlapped on the sweep trace that is carried on the intermediate transfer belt 9.

Yet, in fact, read the transfer member position mark and read between the second place mark and produce timing offset.For this reason, change the superficial velocity of photosensitive drums 1M, 1C and 1K, thereby avoid producing timing offset by controlling and driving motor M M, MC and MK.

Therefore, by to the inside Spin Control of photosensitive drums 1M, 1C and 1K with alignment scanning line on the position, eliminated because the inhomogeneous sweep trace that causes of rotation of photosensitive drums 1Y writes the variation of spacing, thereby eliminated the deviation of sweep trace.

In addition, by to photosensitive drums 1M, 1C and 1K have a mind to Spin Control with alignment scanning line on the position, also eliminated because the inhomogeneous sweep trace that causes of rotation of intermediate transfer belt 9 arrives first transfer printing portion (TM, TC, TK: timing Fig. 1) changes, thereby eliminates the deviation of sweep trace.

Be arranged in the downstream of reader 32Y on the inside surface of photosensitive drums 1Y as the erasing apparatus 33Y of primary importance erasure of marks device example.Erasing apparatus 33Y wipes the primary importance mark (221: Fig. 4) of magnetic recording on the inside surface of photosensitive drums 1Y.

Be arranged in the downstream of photosensitive drums 1J on the outside surface of intermediate transfer belt 9 as the erasing apparatus 36 of transfer member position mark erasing apparatus example.Erasing apparatus 36 is wiped the transfer member position mark (521: Fig. 5) of magnetic recording on the inside surface of intermediate transfer belt 9.

The downstream of reader 32M, 32C and 32K on the inside surface that is arranged in photosensitive drums 1M, 1C and 1K as erasing apparatus 33M, 33C and the 33K of second place erasure of marks device example.Erasing apparatus 33M, 33C and 33K wipe the second place mark (222: Fig. 6) of magnetic recording on the inside surface of photosensitive drums 1M, 1C and 1K.

Hereinafter, to describe, therefore omit as the cyan toner image of other example of the second color toner image and the unnecessary explanation of black toner image as the yellow toner image of the first color toner image with as the overlapping control of the pinkish red toner image of the second color toner image.

With reference to Fig. 7 as shown in Figure 8, second place mark 222 is positioned at by being transcribed on the transfer member position mark 251 that forms by primary importance mark 221, thereby eliminates the sweep trace deviation between yellow toner image and the pinkish red toner image.

Control section 110 forms the color image of corresponding yellow, cyan, magenta and black by image information, and by the corresponding color image that decompresses prepare scan-line data (S11, S21).

The scanning regularly synchronous (S12) of 111 control writing station 31Y of primary importance label record portion and exposure device 3Y, thus primary importance mark 221 (S13) on photosensitive drums 1Y, formed.

The exposure device 3Y that forms the device example as the first static picture is used for the scan-line data of yellow image electrostatic image is write photosensitive drums 1Y (S14) by use.Electrostatic image is developed into yellow toner image as the first color toner image example by the developing apparatus 4Y as the first developing apparatus example.

The scanning regularly synchronous (S22) of 112 control writing station 31M of second place label record portion and exposure device 3M, thus second place mark 222 (S23) on photosensitive drums 1M, formed.

The exposure device 3M that forms the device example as the second static picture is used for the scan-line data of pinkish red image electrostatic image is write photosensitive drums 1M (S24) by use.Electrostatic image is developed into pinkish red toner image as the second color toner image example by the developing apparatus 4M as the second developing apparatus example.

The sweep trace that is used for yellow image moves (S15) by the rotation of photosensitive drums 1Y, and feasible reader 32Y as primary importance mark detecting apparatus example detects primary importance mark 221 (S16).

Transfer member position mark recording portion 113 is controlled the detection regularly synchronous (S16) as the writing station 34Y of transfer member position mark pick-up unit example and primary importance mark 221, thereby forms transfer member position mark 251 on intermediate transfer belt 9.

Simultaneously, at the first transfer printing portion TY place as the first transfer printing portion example, the sweep trace that is used for yellow image is transferred to intermediate transfer belt 9 for the first time.

The sweep trace that is used for yellow image moves (S8) by the rotation of intermediate transfer belt 9, and feasible reader 35M as transfer member position mark pick-up unit example detects transfer member position mark 251 (S19).

The sweep trace that is used for pinkish red image moves (S25) by the rotation of photosensitive drums 1M, and feasible reader 32M as second place mark detecting apparatus example detects second place mark 222 (S26).

The detection of the second place mark 222 that speed controlling portion 114 will obtain by the reader 32M regularly detection timing (S19) of (S26) and the transfer member position mark 251 that obtains by reader 35M compares (S27).

Speed controlling portion 114 begins the timing of transfer member position mark 251 when reader 35M detects as shown in Figure 5 beginning label 241.

Speed controlling portion 114 countings are corresponding to the detection time of each transfer member position mark 251 of the formation of the related scans line in first image-region.

Speed controlling portion 114 stops the timing to transfer member position mark 251 when reader 35M detects end mark 261.

Speed controlling portion 114 begins the timing of second place mark 222 when reader 32M detects as shown in Figure 6 beginning label 212.

Speed controlling portion 114 countings are corresponding to the detection time of each second place mark 222 of the formation of the related scans line in second image-region.

Speed controlling portion 114 stops the timing to second place mark 222 when reader 32M detects end mark 232.

The rotation of speed controlling portion 114 control photosensitive drums 1M, make that the difference of count value is zero between transfer member position mark 251 and the second place mark 222, thereby the sweep trace that will be used for pinkish red toner image accurately overlaps the sweep trace (S28) that is used for yellow toner image.

Speed controlling portion 114 as the control device example obtains second place mark 222 delays with respect to corresponding transfer member position mark 251 (in advance) amount, and increases the speed of (reducing) drive motor MM according to this delay (in advance) amount.Therefore, the rotational speed of photosensitive drums 1M increases (reducing), thereby makes second place mark 222 and transfer member position mark 251 arrive the first transfer printing (TM: Fig. 1) of portion simultaneously.

Fig. 9 is a process flow diagram of carrying out control procedure shown in Figure 8.

With reference to Fig. 7 as shown in Figure 9, whole control process is described by five tasks that are divided into shown in Figure 10-14.

Receiving imaging when work, control section 110 is imaging prepare (S31) by intermediate transfer belt 9 being rotated in advance come.

Before exposure device 3Y began to write electrostatic image, primary importance label record portion 111 began task 1 (S32) when time t=0.Task 1 is that primary importance mark 221 is recorded in (S32) among the photosensitive drums 1Y.

Exposure device 3Y produces and the timing signal synchronous with respect to the raster scanning of photosensitive drums 1Y.Primary importance label record portion 111 is according to raster scanning timing controlled writing station 31Y, so that record is used for the primary importance mark 221 of yellow image.

Transfer member position mark recording portion 113 is (S33 is for being) beginning task 3 (S34) from (t=0) elapsed time θ of task 1/w the time.Here, the angle of " θ " expression from the exposure position of photosensitive drums 1Y to the first transfer printing TY of portion, the angular velocity of rotation of " w " expression photosensitive drums 1Y.

Task 3 is that position mark is transcribed into transfer member position mark 251 (S34) on the intermediate transfer belt 9 from being formed on primary importance mark 221 on the photosensitive drums 1Y.

Concerning reading primary importance mark 221 each time by reader 32M, transfer member position mark recording portion 113 activates writing station 34 to form transfer member position mark 251.

Second place label record portion 112 is (S35 is for being) beginning task 2 (S36) from task 1 (t=0) elapsed time l/v the time.Here, the distance of " l " expression from the first transfer printing TY of portion to the first transfer printing TM of portion, the circular velocity of " v " expression intermediate transfer belt 9.Task 2 is second place mark 222 to be recorded in photosensitive drums 1M go up (S36).

Exposure device 3M produces and the timing signal synchronous with respect to the raster scanning of photosensitive drums 1M.Second place label record portion 112 is according to raster scanning timing controlled writing station 31M, so that record is used for the second place mark 222 of pinkish red image.

Speed controlling portion 114 is from (t=l/v) elapsed time of task 2 ((S37 is for being) beginning task 4 and 5 (S38) during θ/w).

Task 4 is to read the second place mark 222 (S38) that is formed on the photosensitive drums 1M by reader 32M.As the positional information of the sweep trace that is used for pinkish red toner image, the number of division and the detection time of second place mark 222 are kept in the register.

Task 5 is the rotational speeies according to the control of the comparative result between transfer member position mark 251 and the second place mark 222 photosensitive drums 1M.

Speed controlling portion 114 reads the transfer member position mark 251 that is formed on the intermediate transfer belt 9 by reader 35M, and transfer member position mark 251 that reads and the second place mark 222 that reads in task 4 are compared.

With reference to Fig. 4 and 7 as shown in figure 10, the 111 control writing station 31Y of primary importance label record portion are to execute the task 1.The raster scanning timing signal be included in raster scanning begin before the commencing signal that sends of the schedule time, with synchronous grating signal of the raster scanning of exposure device 3Y and the end signal that after raster scanning is finished, sends immediately.

Primary importance label record portion 111 forms beginning label 211 (S53) in the timing (S52 is for being) of commencing signal, and forms end mark 231 (S44) in the timing (S54 is for being) of end signal.Timing (S54 is for denying) in grating signal forms the first image bearing member position mark 221 (S56).

With reference to Fig. 6 and 7 as shown in figure 11, second place label record portion 112 executes the task 2 by control writing station 31M.The raster scanning timing signal be included in raster scanning begin before the commencing signal that sends of the schedule time, with synchronous grating signal of the raster scanning of exposure device 3M and the end signal that after raster scanning is finished, sends immediately.

Second place label record portion 112 forms beginning label 212 (S63) in the timing (S62 is for being) of commencing signal, and forms end mark 232 (S64) in the timing (S64 is for being) of end signal.Timing (S64 is for denying) in grating signal forms the second image bearing member position mark 222 (S66).

With reference to Fig. 5 and 7 as shown in figure 12, transfer member position mark recording portion 113 executes the task 3 by control reader 32Y.

Transfer member position mark recording portion 113 forms beginning label 241 (S73) in the timing that detects beginning label 211 (Fig. 4) (S72 is for being), and forms end mark 261 (S74) in the timing that detects end mark 231 (S74 is for being).The timing that detects beginning label 211 (S74 is for denying), form transfer member position mark 251 (S76).

With reference to Fig. 6 and 7 as shown in figure 13, speed controlling portion 114 executes the task 4 by control reader 32M.

Speed controlling portion 114 detects beginning labels 212 (S82 is for being) and also begins to detect second place mark 222, subsequently for each detection executive logging detection time (S85) of second place mark 222 with count (S86).(S87 is for being) finishes the detection of second place mark 222 when detecting end mark 232.

With reference to Fig. 5 and 7 as shown in figure 14, speed controlling portion 114 executes the task 5 by controlling and driving motor M M on the basis of reader 35M.

For detecting transfer member position mark 251 (S93 is for being) on the intermediate transfer belt 9 by reader 35M each time, speed controlling portion 114 will and store into detection time in the register since (position) quantity of the transfer member position mark 251 of the first transfer member position mark 251 (S94, S95).

In the detection of second place mark 222 regularly and under the situation of the detection of transfer member position mark 251 (S97 is for being) regularly closer to each other, the difference (S98) of detection time between speed controlling portion 114 calculating second place marks 222 and the transfer member position mark 251.

In the detection of second place mark 222 regularly and the detection of transfer member position mark 251 regularly each other under the situation of deviation (S97 for not), the difference (S99) of quantity between speed controlling portion 114 calculating second place marks 222 and the transfer member position mark 251.

Speed controlling portion 114 changes the rotational speed of drive motor MM, so that elimination difference detection time or (position) quantity variance (S100).

When reader 35M detects end mark 261 (S101 is for being), speed controlling portion 114 is finished the control of drive motor MM.

Incidentally, in the aliasing error between the sweep trace of spacing 42 μ m (colour tolerance) is under the situation of 10 μ, and the resolution characteristic of each is about 1 μ m satisfactorily in primary importance mark 221, transfer member position mark 251 and the second place mark 222.

In embodiment 1,, and detect simulating signal from recording figure forming by in two readers of the 10.5 μ m that stagger each other along sense of rotation each for each sweep trace is carried out the sinusoidal wave shape magnetic recording with cycles 42 μ m.By these two detected simulating signals are carried out signal Processing, one-period is divided into the resolution characteristic of 64 subcycles to realize wishing.

In addition, stagger each other along sense of rotation by using that to detect spacings be the scale of the magnetic recording of 100 μ m for two readers of 1/4 signal period, can one-period be divided into the resolution characteristic that 128 subcycles are realized wishing by using signal Processing.

In addition, undertaken by the ring head that uses 1 μ m gap under the situation of the horizontal magnetic recording of 4 μ m in the ferrite magnetic recording layer, can carry out the resolution characteristic that interpolation realizes wishing by using four subcycles telling by the one-period of the simulating signal that reads itself.

The writing position that it is desirable for writing station 31Y (31M) can overlap with the laser scanning position for the rotation angle direction of photosensitive drums 1Y (1M).In addition, it is desirable for writing to begin to be timed to and not having time delay of sweep trace from the photosensitive drums 1Y (1M) by writing station 31Y (31M) record primary importance mark 221 (second place marks 222).

Yet, in fact can produce certain time delay.For example, be under the situation of 300mm/sec in processing speed, when be 30 μ sec time delay, produce the aliasing error (aberration) of about 10 μ m.In processing speed is under the situation of 300mm/sec, when the desired value of the aberration limit is 10 μ m or more hour, be 30 μ sec or shorter permissible time delay.

Under time delay debatable situation, can be by the writing position of writing station 31Y (31M) be eliminated error with respect to the sense of rotation of photosensitive drums 1Y (1M) with the downstream that the distance corresponding to time delay is positioned at the laser scanning position on the photosensitive drums 1Y (1M).Primary importance mark 221 (second place mark 222) be used for before write relative position, the position of sweep trace of electrostatic image to be recorded time delay.

In addition, the writing position that it is desirable for writing station 34 can be set up tight position overlapped relation by the position of reading of the first transfer printing of being rotated in of photosensitive drums 1Y portion TY place and reader 32Y.The detection that it is desirable for the primary importance mark 221 from the photosensitive drums 1Y is timed to by not having time delay between the writing station 34 record transfer member position marks 251.

Yet, in fact can produce certain time delay.

For this reason, the writing position that it is desirable for writing station 34 is positioned at the downstream of reading the position of reader 32Y with the distance corresponding to time delay with respect to the sense of rotation of photosensitive drums 1Y.Transfer member position mark 251 in the position relative with the position of the primary importance mark 221 that reads before with record time delay.

In addition, it is desirable for the position of reading of reader 35M can reading the position and set up tight position overlapped relation by the first transfer printing of being rotated in of photosensitive drums 1M portion TM place and reader 32M.The detection that it is desirable for the second place mark 222 from the photosensitive drums 1M is timed to increase between the rotational speed of (reducing) photosensitive drums 1M by speed controlling portion 114 does not have time delay.

Yet, in fact can produce certain time delay.

For this reason, it is desirable for the position is positioned at reader 32Y with the distance corresponding to time delay with respect to the sense of rotation of the first transfer printing TM of portion the upstream of reading the position of reading of reader 35M and 32M.

In addition, in embodiment 1, primary importance mark 221, transfer member position mark 251 and second place mark 222 be formed on toner image load-bearing surface facing surfaces on, make these position marks can also be formed on these position marks and toner image bidimensional position overlapped place.Yet, under primary importance mark 221, transfer member position mark 251 and second place mark 222 are formed on situation on the toner image load-bearing surface, it is desirable for these position marks is formed on beyond the image-region with respect to the longitudinal direction of the Width of intermediate transfer belt 9 and photosensitive drums 1Y and 1M.

According to the control among the embodiment 1, in the toner image that is provided with a plurality of imagings station PY, PM, PC and PK and different colours in turn is transferred to this so-called tandem type imaging device on the intermediate transfer belt 9 for the first time, might fully proofread and correct the color coincidence deviation relevant with sub scanning direction.

＜embodiment 2 〉

Figure 15 is the synoptic diagram that shows the exposure control among the embodiment 2, and Figure 16 is the synoptic diagram that shows the angle index reader.

In embodiment 2, fixing optical scale is formed on first image bearing member (1Y) (second image bearing member (1M)), and electrostatic image and optical scale read timing detection and synchronously be formed on first image bearing member (1Y) (second image bearing member (1M)).It is not to write by scanning sweep trace is write on first image bearing member (1Y) (second image bearing member (1M)) that the first static picture forms device (3Y) (the second static picture forms device (3M)), writes a sweep trace together but have regular a plurality of illuminated components (led array) of (equidistantly) at interval by use.Other compositions are identical with embodiment 1, therefore omitted explanation and unnecessary explanation.

The angle index 42Y (primary importance mark) of the optical design that integrally rotates with photosensitive drums 1Y is connected on the photosensitive drums 1Y.The angle index 42M (second place mark) of the optical design that integrally rotates with photosensitive drums 1M is connected on the photosensitive drums 1M.

Read angle index 42Y (42M) as the first transfer member position mark pick-up unit example with as the reader 41Y (41M) of pick-up unit example regularly, and read output signal is sent to exposure control part 43Y (43M) as the apparatus for controlling example.

Exposure device 3Y and 3M be arranged in as shown in Figure 3 photosensitive drums 1Y and the exposure position place of 1M, and make with pel spacing and be arranged in each illuminated in combination in numerous LED elements on the sweep trace with different loads and brightness.

Exposure control part 43Y and 43M are according to the timing that produces trace interval from the read output signal of reader 41Y and 41M.

In each timing that is produced by exposure control part 43Y and 43M, led array is to activate with the sweep trace view data corresponding exposure amount that obtains by control section 110, so that jointly sweep trace is write on the surface of each photosensitive drums 1Y and 1K.

In embodiment 2, the stationkeeping that writes on the sweep trace on photosensitive drums 1Y and the 1M makes scan line position count by the scale of reader 41Y and 41M and distinguishes on angle index 42Y and 42M.

With reference to Figure 15 as shown in Figure 9, after beginning task 1, the time reaches θ/w (S33 is for being) at the count value place with the corresponding angle index 42Y of θ, thereby by using writing station 34 beginning tasks 3 (S34).

In addition, the time and first transfer printing TY of portion and TM between reach l/v (S35 is for being) apart from the count value place of the corresponding angle index 42Y of l, thereby utilize exposure device 3M to begin task 2 (S36).

Time with the angle θ of photosensitive drums 1Y right girth and reach (θ/w+l/v) (S37 is for being) apart from the corresponding count value of l sum place.Then, use reader 41M and 35M and drive motor MM to begin the control (S38) of task 4 and 5.

As shown in figure 16, as angle index 42Y and 42M, form by 100 μ m cycles and reflect/increment type optical scale that black pattern is formed.

Reader 41Y and 41M comprise sensor substrate 45, be furnished with on it as light source light emitting diode (LED) 47 and as the photosensor array 46 of read element.The light that sends from LED47 enters photosensor array 46 by angle index 42Y and 42M reflection.

The reflected light that enters photosensor array 46 provides the corresponding LO-pattern of spacing with each angle index 42Y and 42M, and moves by the rotation of each photosensitive drums 1Y and 1M.According to the spacing of each angle index 42Y and 42M, from with the photosensor array 46 output analog sine voltage signals of the corresponding pitch arrangement of LO-pattern.

As described in embodiment 1, photosensor array 46 with reflect with 100 μ m cycles/the corresponding mode of 1/4 cycle of black pattern arranges in pairs.This angle sine voltage signal to photosensor array portion 46 is subjected to signal Processing, so that 100 μ m cycles were divided into 128 subcycles, make and realizes 1 μ m or the following resolution characteristic of 1 μ m.

At exposure device 3Y and 3M is under the situation of laser beam flying exposure device as described in example 1 above, can only select the write timing of sweep trace at the limited phase position place of the used rotating mirror of scanning.Yet, utilizing led array as described in example 2 above to write under the situation of the exposure device 3Y of sweep trace and 3M the change that the sweep trace write timing can be continuous, random by common exposure.

＜embodiment 3 〉

Figure 17 is the synoptic diagram that shows the inclination control of the photosensitive drums among the embodiment 3.Figure 18-20 is respectively side view, front view and the planimetric map of the tilt adjusting mechanism of photosensitive drums.

In embodiment 1, the rotational speed of control photosensitive drums 1M, make the transfer member position mark (251: Fig. 5) and second place mark (222: the difference of count value is zero Fig. 6).In addition, primary importance mark and second place mark by magnetic recording on the inside surface of first image bearing member and second image bearing member, and the transfer member position mark by transcribing by the primary importance mark by magnetic recording on the inside surface of transfer member.

In contrast to this, in embodiment 3, the inclination of control photosensitive drums 1M, thereby by being zero with the axle of photosensitive drums 1M along the difference in count that the sense of rotation of intermediate transfer belt moves between the second place mark that slight distance makes the transfer member position mark of transfer member and second image bearing member.Second image bearing member rotatablely moves in the plane of transfer member, is carried on the sweep trace on second image bearing member and is carried on inclination between the sweep trace on the transfer member with elimination.In addition, primary importance mark and second place mark are configured for the both side ends of the sweep trace of the electrostatic image on first image bearing member, and electrostatic image utilizes toner to write and develop, to be formed on first image bearing member.

Be transferred on the transfer member by the first transfer printing portion TY place that a pair of primary importance is marked at as the first transfer printing portion example, the transfer member position mark is arranged in pairs in two end position places with respect to the Width vertical with the moving direction of transfer member.

In embodiment 3, other compositions are identical with embodiment 1 basically, therefore omit explanation and unnecessary explanation.In addition,, be arranged in of reference number or the symbolic representation of the member of front side, be arranged in of reference number or the symbolic representation of the member of rear side with band suffix b with band suffix a for used member among the embodiment 1.

As shown in Figure 7, be formed on primary importance mark 221a on the photosensitive drums 1Y, thereby form transfer member position mark 251a in the transfer printing of the front side of intermediate transfer belt 9.Be formed on primary importance mark 221b on the photosensitive drums 1Y in the rear side transfer printing of intermediate transfer belt 9, thereby form transfer member position mark 251b.

Primary importance mark 221a and 221b write photosensitive drums (1Y: Fig. 3), with as will be by exposure device (3Y: Fig. 2) write on the end, front and back of the sweep trace outside the full-size image, and develop by developing apparatus 4Y.Yet, when primary importance mark 221a and 221b form with respect to all sweep traces, form same image, thereby can not distinguish sweep trace.For this reason, primary importance mark 221a and 221b form with the ratio of a primary importance mark of per three sweep traces.

Primary importance mark 221a and 221b arrange that with the interval of 84 μ m the toner image of 42 μ m is arranged in the described interval.In addition, as shown in Figure 4, long beginning label 211a and 211b and end mark 231a and 231b correspondingly are formed on the image-region.Beginning label 211a and 211b and end mark 231a and the first transfer printing of 231b are on intermediate transfer belt 9, so that beginning label 241a and 241b and end mark 261 and 262b to be provided respectively, as shown in Figure 5.

As shown in Figure 1, after control is finished, transfer member position mark 251a and 251b and overlapping and be sent to the T2 of secondary transfer printing portion at the second place mark 222a of first transfer printing portion TM place transfer printing and 222b.Then, transfer member position mark 251a and 251b, remove by the secondary transfer roller cleaning device (not shown) that is provided with for secondary transfer roller on secondary transfer roller 11 then from middle transfer belt 9 secondary transfer printings.

Be used to detect the reader 32Ma of second place mark 222a and 222b and 32Mb the developing apparatus that is provided with along photosensitive drums 1M (4M: Fig. 2) and the position between the first TM of transfer printing portion begin equidistantly to arrange from the first transfer printing TM of portion.

Equal the distance from the first transfer printing TM of portion to reader 32Ma (32Mb) along the distance of intermediate transfer belt 9 along photosensitive drums 1M from the first transfer printing TM of portion to reader 35Ma (35Mb).Therefore, second place mark 222a (222b) and the corresponding transfer member position mark 251a (251b) that is detected simultaneously by reader 32Ma (32Mb) and reader 35Ma (35Mb) overlaps each other at first transfer printing portion TM place.

Therefore, the amount of movement of control photosensitive drums movement actuator 48a, feasible is zero by the count value of the detected second place mark of reader 32Ma 222a with by the difference between the count value of the detected transfer member position mark of reader 35Ma 251a.In addition, the amount of movement of control photosensitive drums movement actuator 48b, feasible is zero by the count value of the detected second place mark of reader 32Mb 222b with by the difference between the count value of the detected transfer member position mark of reader 35Mb 251b.In the present embodiment, photosensitive drums movement actuator 48a constitutes pick-up unit, with the position of adjusting photosensitive drums with respect to intermediate transfer direction of belt travel (transfer member moving direction), thereby avoids aberration.

Therefore, the difference that moves aspects such as (motion) speed, expansion and amount of contraction of the diameter of the photosensitive drums 1Y between front side and the rear side, the diameter of photosensitive drums 1M, intermediate transfer belt 9 is able to accurate correction, thereby the second color toner image is accurately overlapped on the first color toner image.

As shown in figure 18, bearing 57a and 57b two ends being supported on U-shaped processing unit chassis 54 of photosensitive drums 1M by being used for two of photosensitive drums 1M end axles.

The axle of photosensitive drums 1M is connected on the photosensitive drum-driving unit 58 that is supported by processing unit chassis 54, makes photosensitive drums 1M by photosensitive drum-driving unit 58 driven in rotation.

The reader 32Ma (32Mb) that is used to detect the reader 35Ma (35Mb) of transfer member position mark 251a (251b) and is used to detect second place mark 222a (222b) is fixed to the end of supporting member 59a (59b).The other end of supporting member 59a (59b) is fixed on the sidepiece chassis 56a (56b).

In embodiment 3, reader 35Ma (35Mb) and reader 32Ma (32Mb) are arranged in the upstream of the first transfer printing TM of portion, but also can be arranged in the next door of transfer device 5M corresponding to the first transfer printing TM of portion.

As shown in figure 19, the laser that sends from exposure device 3M passes the surface of the opening 60 and the scanning photosensitive drums 1M on processing unit chassis 54.Processing unit chassis 54 is by being moved by photosensitive drums movement actuator 48a and 48b driving.

For processing unit chassis 54, charging device 2M, exposure device 3M, developing apparatus 4M, first transfer device 5M and cleaning device 6M are arranged on around the photosensitive drums 1M with fixing position relation.For this reason, charging device 2M, exposure device 3M, developing apparatus 4M, first transfer device (roller) 5M and cleaning device 6M are driven by photosensitive drums movement actuator 48a and 48b, to move with photosensitive drums 1M.By the position relation between these devices and the photosensitive drums 1M is remained on constant level, image-forming condition does not change, thereby can carry out stable imaging.

Imaging station PM rotatably supports by the middle movable chassis 51 of bearing by U-shaped.Bolster 52 is arranged on the middle part of going up on processing unit chassis 54.

Part place at sidepiece chassis 56a and 56b and photosensitive drums movement actuator 48a and 48b relative positioning is provided with the compression spring 63a and the 63b that are used for processing unit chassis 54 is pushed to photosensitive drums movement actuator 48a and 48b.

As shown in figure 20, middle movable chassis 51 in two end by only movably linear guides 55a and 55b are supported by sidepiece chassis 56a and 56b respectively along the sense of rotation of intermediate transfer belt 9.

Sidepiece chassis 56a and 56b are fixed on the equipment master component chassis that does not show, movable chassis 51 can move abreast with the sense of rotation of intermediate transfer belt 9 in the middle of making.

The two ends that comprise the imaging station PM of photosensitive drums 1M can independently be moved along the sense of rotation of intermediate transfer belt 9, make that photosensitive drums 1M not only can be along the sense of rotation translation of intermediate transfer belt 9, and can change the inclination angle in the plane of intermediate transfer belt 9.

Displacement transducer 62a and 62b are arranged on sidepiece chassis 56a and 56b top, and described displacement transducer is used to measure the displacement of surperficial 61a of the displacement measurement of handling unit chassis 54 and 61b.Displacement transducer is arranged on the two ends of imaging station PM, and output is fed to photosensitive drums movement actuator 48a and 48b, thereby is embodied as the high precision position control of picture station PM.

Turning axle at photosensitive drums 1M moves along intermediate transfer belt 9 under the situation of control, and the exposure position that photosensitive drums 1M is exposed device 3M exposure is affected.Yet, the variation that causes owing to this influence also is recorded among the photosensitive drums 1M as second place mark, even make that pinkish red toner image also can accurately overlap on the yellow toner image when affected pinkish red toner image arrives the first transfer printing TM of portion.

＜embodiment 4 〉

Figure 21 is the synoptic diagram that shows the used structure of control among the embodiment 4, and Figure 22 is the block diagram that shows the control summary among the embodiment 4.

In embodiment 1, for write sweep trace at every turn, primary importance mark, second place mark and transfer member position mark form again corresponding to the position of sweep trace, and after using, wipe primary importance mark and second place mark.

In embodiment 4, the primary importance mark is prepared in advance with respect to first image bearing member, as the fixedly scale of arranging along the sense of rotation of first image bearing member, and for each formation of sweep trace, fixedly scale pick-up unit detection primary importance label fixed scale.Using fixedly, the primary importance marked address of scale is kept in the memory storage.

In addition, second place mark is prepared in advance with respect to second image bearing member, as the fixedly scale of arranging along the sense of rotation of second image bearing member, and for each formation of sweep trace, fixedly scale pick-up unit detection second place label fixed scale.Using fixedly, the second place marked address of scale is kept in the memory storage.

In addition, the transfer member position mark is prepared in advance with respect to transfer member, as the fixedly scale of arranging along the moving direction of transfer member, and fixedly the scale pick-up unit detects fixedly scale with the synchronous transfer member position mark of primary importance label fixed scale.Use fixedly that the primary importance marked address of scale is kept in the memory storage, fixedly the address of the transfer member position mark of scale is corresponding with use.As mentioned above, arbitrary position mark fixed and arranged.

In embodiment 5, other compositions are identical with embodiment 1 basically, therefore omit explanation and unnecessary explanation.

As shown in figure 21, the primary importance mark 221 1 complete cycle ground of fixing connect or imprint on photosensitive drums 1Y.Similarly, the second place mark one complete cycle ground of fixing connects or imprints on photosensitive drums 1M.Similarly, the transfer member position mark 251 1 complete cycle ground of fixing connect or imprint on intermediate transfer belt 9.

Primary importance mark 221, second place mark 222 and transfer member position mark 251 form by the method for for example attached subsides band shape scale, scale printing or engraving.

In the control of embodiment 4, in order to discern photosensitive drums 1Y and 1M and intermediate transfer belt 9 position with respect to surperficial sense of rotation, scale is absolute encoder pattern or the incremental encoder pattern with initial point mark.Under the situation of absolute encoder pattern, reader 38Y reads the scale of the primary importance mark 221 that is fixed on the photosensitive drums 1Y, and the output specific address.Under the situation of the incremental encoder pattern with initial point mark, reader 38Y reads the scale of the primary importance mark 221 that is fixed on the photosensitive drums 1Y, and output is from the calibration gauge numerical value of initial point meter.

Have at these patterns under the situation of track of increment type optical design, track can be made of angle index 42Y shown in Figure 16 and 42M, thereby can be read device 41Y and 41M reads.

Therefore, be divided into the positional information of 64 sections or 128 sections with regard to exportable by two simulating signals that read from the optical design in 100 μ m cycles (spacing) in the position of moving for 1/4 cycle being carried out signal Processing.

With reference to Figure 21 as shown in figure 22, the address translation of primary importance mark 221 is the address of transfer member position mark 251, and on the position with the address align of second place mark 222, thereby eliminate sweep trace deviation between yellow toner image and the pinkish red toner image.

Control section 110 by the corresponding coloured image that decompresses prepare scan-line data (S11, S21).

Exposure device 3Y is used for yellow image by use scan-line data with electrostatic image write on photosensitive drums 1Y (S12, S13).

Exposure device 3M is used for pinkish red image by use scan-line data with electrostatic image write on photosensitive drums 1M (S22, S23).

The control reader 38Y of primary importance label record portion 111 to be reading primary importance mark 221, thus the address (S111) of formation photosensitive drums 1Y constantly one by one.

The address (S112) that primary importance label record portion 111 utilizes primary importance mark 221 and the scanning of exposure device 3Y in the storer 106 regularly synchronously to preserve photosensitive drums 1Y.The positional number of the address of the photosensitive drums 1Y that is formed by fixing primary importance mark and the sweep trace that is used for yellow toner image that forms by the raster scanning timing signal of counting from exposure device 3Y is kept at storer 106 with man-to-man relation.

Table 1

-------------------------------------------------

The first photosensitive drums address, the first picture position information

99 1

1010 2

1020 3

1029 4

1039 5

1051 6

1060 7

1069 8

1081 9

1091 10

2000 11

2010 12

2019 13

2031 14

2040 15

2049 16

2061 17

2071 18

. .

. .

. .

-------------------------------------------------------

The 112 control reader 38M of second place label record portion read second place mark 222, thereby form the address (S121) of photosensitive drums 1M one by one constantly.

The address (S122) that second place label record portion 112 utilizes second place mark 222 and the scanning of exposure device 3M in the storer 105 regularly synchronously to preserve photosensitive drums 1M.The positional number of the address of the photosensitive drums 1M that is formed by fixing second place mark and the sweep trace that is used for pinkish red toner image that forms from the raster scanning timing signal of exposure device 3M by counting is kept at storer 105 to concern one to one.

Table 2

------------------------------------------------

The second photosensitive drums address, the second picture position information

------------------------------------------------

1056 1

1066 2

1075 3

1086 4

1097 5

1106 6

1115 7

1124 8

1136 9

1145 10

1154 11

1164 12

1175 13

1187 14

1195 15

2004 16

2014 17

2025 18

. .

. .

. .

------------------------------------------------

Incidentally, when the time that the scale from reader 38Y and 38M reads signal and raster scanning signal is not inconsistent each other, just read the address of signal and the positional number of raster scanning signal is preserved accordingly at the scale after the raster scanning signal before the raster scanning signal or just.Can also optionally preserve with the raster scanning signal more approaching just in address that the scale after the raster scanning signal before the raster scanning signal or just reads signal.

In addition, with similar among the embodiment 1,,, reader 38Y and 38M can eliminate described error by being moved or arrange with the distance corresponding to error towards the downstream reading under the situation that life period postpones (error) of reader 38Y and 38M.Alternatively, the address that can also read when to use positional number and time quantum before time delay the be described time delay method of preserving is accordingly eliminated described error.

By the rotation of photosensitive drums 1Y, primary importance mark 221 moves (S114) and reads (S115) by reader 32Y with the yellow image sweep trace.

Transfer member position mark recording portion 113 control readers 39 read transfer member position mark 251, thereby form the address (S113) of intermediate transfer belt 9 one by one constantly.

(TY: Fig. 1), reader 32Y reads primary importance mark 221, and reader 39 reads transfer member position mark 251 in the first transfer printing portion that contacts with intermediate transfer belt 9 at photosensitive drums 1Y.

The read output signal that transfer member position mark recording portion 113 is handled from reader 32Y, and output specific address when primary importance mark 221 is the absolute encoder pattern, perhaps primary importance mark 221 when having the incremental encoder pattern of initial point output from the calibration gauge numerical value of initial point meter.

The read output signal that transfer member position mark recording portion 113 is handled from reader 39, and output specific address when transfer member position mark 251 is the absolute encoder pattern, perhaps transfer member position mark 251 when having the incremental encoder pattern of initial point output from the calibration gauge numerical value of initial point meter.

The address (S116) that transfer member position mark recording portion 113 utilizes transfer member position mark 251 and the detection of primary importance mark 221 in the storer 108 regularly synchronously to preserve intermediate transfer belt 9.Therefore, the address of the address of the photosensitive drums 1Y that is formed by primary importance mark 221 and the intermediate transfer belt 9 that formed by transfer member position mark 251 is kept in the storer 108 with relation one to one.

Table 3

------------------------------------

The first photosensitive drums address strap address

------------------------------------

999 12528

1010 12538

1020 12547

1029 12558

1039 12569

1051 12580

1060 12589

1069 12600

1081 12609

1091 12621

2000 12630

2010 12640

2019 12651

2031 12661

2040 12670

2049 12679

2061 12688

2071 12699

. .

. .

. .

---------------------------------------

Transfer member position mark recording portion 113 makes yellow toner image (sweep trace (position) number) be associated with the address of intermediate transfer belt 9 by the storer 106 in the reference primary importance label record portion 111.

Data from storer in the key 1 subsequently, correspond to each other the positional information segment of yellow toner image and the address of intermediate transfer belt 9.

Table 4

--------------------------------------------------

The band address first picture position information

--------------------------------------------------

12528 1

12538 2

12547 3

12558 4

12569 5

12580 6

12589 7

12600 8

12609 9

12621 10

12630 11

12640 12

12651 13

12661 14

12670 15

12679 16

12688 17

12699 18

. .

. .

. .

--------------------------------------------------

By the rotation of intermediate transfer belt 9, transfer member position mark 251 moves (S117) and detects (S118) by reader 35M with the yellow image sweep trace.By the rotation of photosensitive drums 1M, second place mark 222 moves (S124) and detects (S125) by reader 32M with pinkish red picture line.

(TM: Fig. 1), reader 32M reads second place mark 222, and reader 35M reads transfer member position mark 251 in the first transfer printing portion that contacts with intermediate transfer belt 9 at photosensitive drums 1M.

The detection of the second place mark 222 that 114 pairs of speed controlling portions are detected by reader 32M regularly (S129) and the transfer member position mark 251 that detects by reader detection regularly (S251) compare (S27).

The data of storer 105 keys 2 of speed controlling portion 114 from second place label record portion 112, and the data of storer 108 keys 4 from transfer member position mark recording portion 113.Then, when reader 35M carries out timing that transfer member position mark 251 detects, the positional information of 114 pairs of yellow toner image of speed controlling portion and the positional information of pinkish red toner image compares and utilization and the corresponding control signal controlling and driving of position deviation amount motor M M.

The rotation of speed controlling portion 114 control photosensitive drums 1M makes that the positional information of the positional information of yellow toner image and pinkish red toner image is consistent each other, thereby pinkish red toner image is accurately overlapped on the yellow toner image.

The data that are kept in the storer 106 are wiped after being read by transfer member position mark recording portion 113 immediately.Therefore, in storer 106, only be preserved for data from the exposure position of photosensitive drums 1Y to the sweep trace of the first transfer printing TY of portion.

The data that are kept in the storer 105 are wiped after being read by speed controlling portion 114 immediately.Therefore, in storer 105, only be preserved for data from the exposure position of photosensitive drums 1M to the sweep trace of the first transfer printing TM of portion.

The data that are kept in the storer 108 are wiped after being read by speed controlling portion 114 immediately.Therefore, in storer 108, only be preserved for exposure position from photosensitive drums 1Y by the data of the first transfer printing TY of portion to the sweep trace of the first transfer printing TM of portion.

The control of using primary importance mark, second place mark and transfer member position mark as fixed pattern to carry out among the embodiment 4 can also be implemented by making photosensitive drums 1M move the control of carrying out along intermediate transfer belt 9 among the embodiment 3.

In addition, have only primary importance mark and second place mark to be subjected to as the control of fixed pattern in embodiment 4, and the transfer member position mark can be subjected to the control in embodiment 1, wherein, the transfer member position mark writes down at every turn when detecting the primary importance mark and wipes after use.

In addition, have only primary importance mark and transfer member position mark to be subjected to as the control of fixed pattern in embodiment 4, and second place mark can be subjected to the control in embodiment 3, wherein, and record when the second place is marked at toner image and is positioned at beyond the image-region of photosensitive drums 1M.

On the other hand, can also use primary importance mark and transfer member position mark, and use second place mark as fixed pattern as the pattern that will write down and wipe.

Therefore, fixed pattern be with record/wiping pattern can carry out different combinations, and the system that makes can design with best of breed according to the performance of imaging device, cost etc.

＜embodiment 5 〉

Figure 43 is the synoptic diagram that shows the used structure of control among the embodiment 5.

In embodiment 4, the reader that is used for second place mark be arranged on photosensitive drums on by exposure device write the close part of the electrostatic image writing position of electrostatic image and near the part of first transfer printing portion these two, thereby be arranged on altogether on two parts with respect to photosensitive drums.

In embodiment 5, the reader that is used for second place mark is the single reader that is arranged on the pre-position with respect to photosensitive drums.

In embodiment 5, other compositions are identical with embodiment 4 basically, therefore omit explanation and unnecessary explanation.

As shown in figure 43, for photosensitive drums 1M, reader 40M is arranged on photosensitive drums 1M and goes up the position of being write the angled θ 1M of electrostatic image writing position of electrostatic image by exposure device 3M.Incidentally, going up the electrostatic image writing position of writing electrostatic image by exposure device 3M from photosensitive drums 1M is θ M to the angle of photosensitive drums 1M and intermediate transfer belt 9 contacted first transfer printing portions (TM).

In addition, photosensitive drums 1Y and intermediate transfer belt 9 contacted first transfer printing portions (TY) and photosensitive drums 1M and intermediate transfer belt 9 contacted first transfer printing portions (TM) are spaced apart at a predetermined distance from each other DP.

The 112 control reader 40M of second place label record portion read second place mark 222, thereby form the address (S121) of photosensitive drums 1M one by one constantly.

The address (S122) that second place label record portion 112 utilizes second place mark 222 and the scanning of exposure device 3M in the storer 105 regularly synchronously to preserve photosensitive drums 1M.At this moment, specified angle θ 1M, so that calculate the second place mark that is positioned at electrostatic image writing position place.The positional number of the address of the photosensitive drums 1M that is formed by second place mark and the sweep trace that is used for pinkish red toner image that forms from the raster scanning timing signal of exposure device 3M by counting is kept at storer 105 to concern (table 2) one to one.

Incidentally, similar to Example 4, read under the situation that signal and time from the raster scanning signal of reader 40M is not inconsistent each other at scale, just read the address of signal and the positional number of raster scanning signal is preserved accordingly at the scale after the raster scanning signal before the raster scanning signal or just.Can also optionally preserve with the raster scanning signal more approaching just in address that the scale after the raster scanning signal before the raster scanning signal or just reads signal.

In addition, reading under the situation that life period postpones (error) of reader 40M, can eliminate error by only considering the second place mark that the distance calculation corresponding with error is positioned at electrostatic image writing position place.Alternatively, can also eliminate described error by using a kind of like this method, in the method, the second place mark that is positioned at electrostatic image writing position place by calculating is preserved the address that positional number reads when time quantum is for time delay before time delay accordingly.

Similar to Example 4, transfer member position mark recording portion 113 makes yellow toner image (sweep trace (position) number) be associated with the address of intermediate transfer belt 9 by the storer 106 in the reference primary importance label record portion 111.

Data from storer in the key 1 subsequently, make the address of the positional information segment of yellow toner image and intermediate transfer belt 9 correspond to each other (table 4).

Concerning the second photosensitive drums address and band address that will between the preparatory stage of table 2 and table 4, preserve, be each predetermined scanning timing setting destination address, wherein, will control to eliminate the sweep trace deviation between yellow toner image and the pinkish red toner image described destination address.That is to say, for each second photosensitive drums address of constantly preserving corresponding to the second picture position information with corresponding to the band address of the first picture position information, the address of regularly being preserved for each predetermined scanning is kept in storer 105 and the storer 108 as destination address TGM and TGI (table 5 and 6).

Table 5

-----------------------------------------------------------------------------

The second photosensitive drums destination address, the second photosensitive drums address, the second picture position information

-----------------------------------------------------------------------------

TGM1(＝1056) 1056 1

- 1066 2

- 1075 3

- 1086 4

- 1097 5

TGM2(＝1106) 1106 6

- 1115 7

- 1124 8

- 1136 9

- 1145 10

TGM3(＝1154) 1154 11

- 1164 12

- 1175 13

- 1187 14

- 1195 15

TGM4(＝2004) 2004 16

- 2014 17

- 2025 18

. . .

. . .

. . .

-----------------------------------------------------------------------------

Table 6

----------------------------------------------------------------------------

The band destination address band address first picture position information

----------------------------------------------------------------------------

TGI1(＝12528) 12528 1

- 12538 2

- 12547 3

- 12558 4

- 12569 5

TGI2(＝12580) 12580 6

- 12589 7

- 12600 8

- 12609 9

- 12621 10

TGI3(＝12630) 12630 11

- 12640 12

- 12651 13

- 12661 14

- 12670 15

TGI4(＝12679) 12679 16

- 12688 17

- 12699 18

. . .

. . .

. . .

----------------------------------------------------------------------------

By the rotation of intermediate transfer belt 9, transfer member position mark 251 moves with the sweep trace of yellow image.At this moment, by the information of table 6, the distance D P between the first transfer printing portion and the specific address that detects by reader 39, might obtain destination address TGI and be positioned at wherein between first transfer printing portion (TY) and the first transfer printing portion (TM).Therefore, the position calculation of destination address TGI is the distance L I apart from first transfer printing portion (TM).

In addition, by the rotation of photosensitive drums 1M, second place mark 222 moves with the sweep trace of pinkish red image.At this moment, information by table 5, go up by exposure device 3M with photosensitive drums 1M and to write the electrostatic image writing position angulation θ M of electrostatic image and the specific address that detects by reader 40M, might obtain destination address TGM and be positioned at photosensitive drums 1M wherein and go up by exposure device 3M and write the electrostatic image writing position of electrostatic image and for the first time between the transfer printing portion (TM).Therefore, destination address TGM may be calculated and the first angulation θ g of transfer printing portion (TM).

Figure 44 is the block diagram of the control summary among the embodiment 5, and Figure 45 is the synoptic diagram that shows the control summary among the embodiment 5.

In the control of present embodiment, carry out the following step in each sampling time of determining.

At first, each begins destination address TGM1 and TGI1 and is considered to want controlled first address (S141).

Obtain the distance L I (S142) of the current first transfer printing portion (TM) of destination address TGI1 on the intermediate transfer belt 9.

By the average translational speed Vp (processing speed of imaging device) of distance L I and intermediate transfer belt 9, obtain the time T g (S143) that destination address TGI1 arrives first transfer printing portion (TM).

In addition, the angulation θ g of current first transfer printing portion (TM) (S144) on acquisition destination address TGM1 and the intermediate transfer belt 9.

By the time T g that obtains in step S143, the photosensitive drums 1M angular velocity of rotation θ ' that obtains to be used to make destination address TGM1 arrive first transfer printing portion (TM) after elapsed time Tg (S145).

Data are recorded in the storer 107b interior (S146) among the drive motor control section 114b.

Drive motor control section 114b controlling and driving motor M M is so that provide anglec of rotation θ ' for photosensitive drums 1M.

Carry out process in each from step S142 to S146 in sampling time, up to one of destination address TGM1 and TGI1 or both arrival set in advance with the off-position R of the position of the distance Lr of first transfer printing portion (TM) (or with the corresponding angle θ r of distance L r) till.Then, all adjust the anglec of rotation θ ' (S147 is for denying) of photosensitive drums 1M at every turn.That is to say that the off-position on the transfer member (precalculated position) R is positioned at the upstream of second TM of transfer printing portion with respect to the transfer member moving direction.In addition, off-position (precalculated position) R on second image bearing member is positioned at the upstream of second TM of transfer printing portion with respect to the second image bearing member sense of rotation.

When one of destination address TGM1 and TGI1 or both arrive off-position R (S147 is for being), destination address TGM that control and TGI are converted to the second destination address TGM2 and TGI2 (S148).

With regard to destination address TGM2 and TGI2, carry out control from step S142 to step S147.

In addition, when one of destination address TGM2 and TGI2 or both arrived off-position R, destination address TGM that control and TGI were converted to the 3rd destination address TGM3 and TGI3.Therefore, each switches destination address TGM and TGI constantly with adjustment angular velocity of rotation θ ', thereby eliminates the sweep trace deviation between yellow toner image and the pinkish red toner image.

Figure 46 (a) and 46 (b) are the block diagrams that shows the summary of the drive motor control section among the embodiment 5.

Control loop 1143a by the use location control system constitutes drive motor control section 114b, shown in Figure 46 (a).The scale information of the second place mark 222 that fixed and arranged is read by reader 40 on photosensitive drums 1M and send to the control loop of position control system by the integrated value of the angular velocity of rotation θ ' of the photosensitive drums 1M of said process (among Figure 46 (a) show piece 1141) decision.Then, according to the comparison of the current location of photosensitive drums 1M, control the rotation of photosensitive drums 1M by the command value of the position rotation aequum sending for drive motor MM to make photosensitive drums 1M.

In addition, shown in Figure 46 (b), drive motor control section 114b also can constitute by the control loop 1143b of operating speed control system.To carrying out integration by the command value that between determined angular velocity of rotation θ ' and current angular velocity of rotation, compares the angular velocity of rotation of acquisition.Then, read the scale information that fixing second place mark 222 obtains, obtain to make the position of photosensitive drums 1M to rotate the command value of aequum and send it to the rotation of drive motor MM with control photosensitive drums 1M by this integrated value with by reader 40.

Incidentally, control system can also be for example to make the scrambler etc. of the positional information be used to obtain photosensitive drums 1M prepare the angular velocity of rotation θ ' with control photosensitive drums 1M separately.

Here, when the servo bandwidth of the control loop 1143a (or control loop 1143b of speed control system) of the position control system of drive motor control section 114b is ω c, off-position R is Lr apart from the distance of first transfer printing portion (TM), setting between destination address TGM and the TGI (interval between the adjacent target) at interval is Δ TG, when the average translational speed of intermediate transfer belt 9 is Vp, satisfy following relationship:

Vp/(Lr+ΔTG)<ωc

Obtained when the destination address that will control from TGM _nAnd TGI _nSwitch to TGM _N+1And TGI _N+1The time make destination address TGM _N+1And TGI _N+1In first transfer printing portion (TM) each other under the situation of the angular velocity of rotation θ ' of consistent photosensitive drums 1M, the left side equals to be used for the reciprocal value of first value of time T g substantially.

In the present embodiment, when destination address TGM and TGI will locate when consistent each other in first transfer printing portion (TM), shown in Figure 46 (a) and 46 (b), the angular velocity of rotation θ ' of photosensitive drums 1M is by being controlled by integrator 1142 integrations.Therefore, under the situation of the angular velocity of rotation θ ' that obtains photosensitive drums 1M, when the inverse of first value that is used for time T g when the value of the servo bandwidth ω c of the control loop 1143a (or control loop 1143b of speed control system) that is not less than position control system begins, system disperses, thereby produces uncontrolled state.Therefore, under the situation of the angular velocity of rotation θ ' that obtains photosensitive drums 1M, the inverse that is used for first value of time T g is defined as the c less than servo bandwidth ω at least.

＜embodiment 6 〉

Figure 23 is the synoptic diagram that shows the formation of the imaging device among the embodiment 6.

In embodiment 6, first image bearing member centers on the inertial mass of the inertial mass of its turning axle greater than second image bearing member.For other compositions, the part identical with embodiment 1 be by identical reference number or symbolic representation, and omit unnecessary explanation.

In embodiment 1 to embodiment 5, just be used to form on first image bearing member and be transferred to regard to each sweep trace of the first color toner image on the transfer member, change a plurality of rotational speeies or the adjoining position of second image bearing member, and each sweep trace that is used for the second color toner image is positioned and overlapping.For this reason, it is less to it is desirable for rotation inequality and circular velocity fluctuation, thereby produces stable rotation according to the order of first image bearing member, transfer member and second image bearing member.

In addition, in embodiment 1, the circular velocity of second image bearing member regularly changes according to the detection of the transfer member position mark of transfer member, but the rotational speed of this image bearing member can always constant circular velocity.

As shown in figure 23, photosensitive drums 1Y and photosensitive drums 1M form the cylindrical shape with same outer diameter as and center on the turning axle that is provided with along cylindrical center's line and rotate, but photosensitive drums 1Y is provided with as the fixedly flywheel 70 that adds inertial mass at its end.For this reason, photosensitive drums 1Y during rotation has the moment of inertia greater than photosensitive drums 1M, thereby is the Spin Control that Constant Angular Velocity is easily carried out photosensitive drums 1Y with stable constant rotational speed.

In addition, even angular velocity of rotation is constant, the interval when circular velocity changes between the sweep trace changes, and makes photosensitive drums Y accurately finish, thereby makes the excentricity of the excentricity of turning axle less than photosensitive drums 1M.

On the other hand, photosensitive drums 1M is not provided with flywheel 70, thereby has little moment of inertia and little inertial mass, makes that the rotational speed of photosensitive drums 1M can be controlled rapidly according to the change of the rotational speed of intermediate transfer belt 9.In addition, quality is very little, thereby can easily control photosensitive drums 1M moving along intermediate transfer belt 9.

Incidentally, the method for comparing the inertial mass that increases photosensitive drums 1Y with photosensitive drums 1M is not limited to flywheel is connected to method on the photosensitive drums 1Y.For example, can also be by comparing the diameter that increases photosensitive drums 1Y with photosensitive drums 1M or comparing the thickness that increases photosensitive drums 1Y with photosensitive drums 1M and realize similar effects.

＜embodiment 7 〉

Figure 24 is the synoptic diagram that shows the used structure of control among the embodiment 7, Figure 25 shows to detect the synoptic diagram of photosensitive drums along the amount of movement of the axial direction of this photosensitive drums, Figure 26 shows the synoptic diagram that is formed on the first width position mark on first image bearing member, Figure 27 shows the synoptic diagram that is formed on the transfer member width position mark on the transfer member, Figure 28 shows the synoptic diagram that is formed on the second width position mark on second image bearing member, Figure 29 is the synoptic diagram that shows distance between the first width position mark and the transfer member width position mark, and Figure 30 is the synoptic diagram that shows distance between the transfer member width position mark and the second width position mark.

In embodiment 1, adjusting gear (regulating device) can be regulated second image bearing member towards the position of transfer member moving direction and be used for the sweep trace of the first color toner image and be used for the position of the sweep trace of the second color toner image with respect to sub scanning direction, thereby makes the second color toner doubling of the image on the first color toner image.

In embodiment 7, adjusting gear (regulating device) can be regulated second image bearing member towards the position of the Width vertical with the transfer member moving direction (image bearing member sense of rotation) and be used for the sweep trace of the first color toner image and be used for the position of the sweep trace of the second color toner image with respect to main scanning direction, thereby makes the second color toner doubling of the image on the first color toner image.

In embodiment 7, similar to Example 4, it is the fixed pattern of first image bearing member, second image bearing member and transfer member that primary importance mark, second place mark and transfer member position mark are prepared in advance, controls subsequently so that described fixed pattern is associated with each other in storer.Therefore, omit making the first color toner image and the second color toner image with respect to the composition of transfer member sense of rotation location and the explanation and the unnecessary explanation of control by detecting fixed pattern.

In embodiment 7, from inner transfer member position mark and the second place mark of detecting of transfer member, described transfer member position mark is arranged on the transfer member surface relative with the transfer member surface that contacts second image bearing member, the end regions of described second place label placement on the outside surface that is positioned at second image bearing member, this end regions stretches out outside the transfer member.

As shown in figure 24, fixing primary importance mark 221 and fixing second place mark 222 are set for photosensitive drums 1Y and photosensitive drums 1M along a complete cycle respectively.Equally, Gu Ding transfer member position mark is arranged on the intermediate transfer belt 9 along a complete cycle.

As described in embodiment 4, specify the position that is formed on the sweep trace on the photosensitive drums 1Y by the address of using primary importance mark 221.The address of using primary importance mark 221 is at (the TY: Fig. 1) locate to be converted to the address of using transfer member position mark 251, so that specify the position by the sweep trace of intermediate transfer belt 9 carryings of first transfer printing portion.

Specify the position that is formed on the sweep trace on the photosensitive drums 1M by the address of using second place mark 222.At the first (TM: Fig. 1) locate, detect transfer member position mark 251 and second place mark 222 independently of transfer printing portion to specify corresponding sweep trace.Then, regulate the rotational speed (perhaps photosensitive drums 1M is along the position of intermediate transfer belt 9) of photosensitive drums 1M, make the address overlap that uses second place mark 222 on the appropriate address that uses transfer member position mark 251.

As shown in figure 25, the length of photosensitive drums 1Y and 1M is greater than the width of intermediate transfer belt 9, and the first width position mark 381 is positioned at beyond the end of intermediate transfer belt 9 broad ways.

When the sweep trace that is used for yellow image was drawn on the photosensitive drums 1Y, exposure device 3Y and predetermined scanning position write the electrostatic image that is used for the first width position mark 381 accordingly.Electrostatic image develops by developing apparatus 4Y, can be by the first width position mark 381 of optical sensor detection to provide.

When the sweep trace that is used for yellow image was drawn on the photosensitive drums 1M, exposure device 3M and predetermined scanning position write the electrostatic image that is used for the second width position mark 382 accordingly.Electrostatic image develops by developing apparatus 4M, can be by the first width position mark 381 of optical sensor detection to provide.

In embodiment 7, the first width position mark 381 and the second width position mark 382 form the straight line of being made up of the preset width direction pixel of arranging along sub scanning direction (sense of rotation), but also but cruciform mark, V-arrangement mark or the like.

On the inner surface of intermediate transfer belt 9, be provided as the transfer member position mark 251 and the transfer member width position mark 385 of fixed pattern, so that be positioned at the inboard, position of the first width position mark 381 and the second width position mark 382 with respect to Width.

The first width position mark 381 and transfer member width position mark 385 are detected simultaneously by a pair of position transducer 71Y and 72Y, and this is maintained fixed along Width layout vertical with the transfer member sense of rotation and mutual alignment relation position transducer.

The second width position mark 382 and transfer member width position mark 385 are detected simultaneously by a pair of position transducer 71M and 72M, and this is maintained fixed along Width layout vertical with the transfer member sense of rotation and mutual alignment relation position transducer.

Position transducer 71Y, 71M, 72Y and 72M measurement as width position mark detecting apparatus example are incident upon the displacement of the image of each mark on the CCD with respect to the CCD center, and export tested displacement with digital value.

The first width position mark 381 and the second width position mark 382 are detected by position transducer 71Y and 71M, are removed by cleaning device 7Y and 7M subsequently.

As shown in figure 26, the first width position mark 381 is recorded in the position with first image-region L spaced a predetermined distance from, wherein, will form the full-size image in described first image-region.

As shown in figure 27, at the inner surface place of intermediate transfer belt 9, form transfer member position mark 251 and transfer member width position mark 385 as fixed pattern.

As shown in figure 28, the second width position mark 382 is recorded in the position with second image-region L spaced a predetermined distance from, wherein, will form the full-size image in described second image-region.

As shown in figure 27, when first image-region at first transfer printing portion TY place when photosensitive drums 1Y is transferred on the intermediate transfer belt 9 for the first time, the first width position mark 381 and transfer member width position mark 385 separate each other with the distance between the label L TY.Then, as shown in figure 25, the distance between the first label L TY of TY place of transfer printing portion calculates by the measured value of position transducer 71Y and 72Y.

As shown in figure 27, when second image-region at first transfer printing portion TM place when photosensitive drums 1M is transferred on the intermediate transfer belt 9 for the first time, the second width position mark 382 and transfer member width position mark 385 separate each other with the distance between the label L TM.Then, as shown in figure 25, the distance between the first label L TM of TM place of transfer printing portion calculates by the measured value of position transducer 71M and 72M.

With reference to Figure 24 as shown in figure 29, when reader 35Y read transfer member position mark 251, width position control part 116 calculated the band address, and this band address descriptor is carried on the position of each sweep trace on the intermediate transfer belt 9.Simultaneously, width position control part 116 is included the measured value that is recorded by position transducer 71Y and 72Y in, and calculating is used for adjacent marker L11, the L12 of each sweep trace, the distance between the L13.....

Distance between position transducer 71Y and the 72Y is fixing.This distance is L1.The departure of the first width position mark of being measured by position transducer 71Y 381 is Δ D1.The departure of the transfer member width position mark of being measured by position transducer 72Y 385 is Δ B1.

Width position control part 116 according to following formula calculate label L 1i (i=1,2,3 ...) and between distance:

L1i＝L1+ΔD1i+ΔB1i

Width position control part 116 is preserved label L 11 accordingly with the band address in the storer 104, L12, L13 ... between the data of distance, as shown in table 7.

Table 7

------------------------------------------------------

Distance between the band address main sweep mark

------------------------------------------------------

15523 L11

15524 L12

15525 L13

15526 L14

15527 L15

15528 L16

15529 L17

15530 L18

. .

. .

. .

----------------------------------------------------

With reference to Figure 24 as shown in figure 30, when reader 35M read transfer member position mark 251, width position control part 116 was specified the band address, and reads corresponding sweep trace from storer 104.Simultaneously, width position control part 116 is included the measured value that is recorded by position transducer 71M and 72M in, and calculates the adjacent marker L21 be used for each sweep trace, L22, L23 .... between distance.

Distance between position transducer 71M and the 72M is fixing.This distance is L1.The departure of the first width position mark of being measured by position transducer 71M 382 is Δ D2.The departure of the transfer member width position mark of being measured by position transducer 72M 385 is Δ B2.

Width position control part 116 according to following formula calculate label L 2i (i=1,2,3 ...) and between distance:

L2i＝L2+ΔD2i+ΔB2i

Width position control part 116 control movement actuator 73M, make first transfer printing portion (TY: Figure 29) locate label L 11, L12 ... between distance equal first transfer printing portion TM place label L 21, L22 ... between distance.Therefore, photosensitive drums 1M moves along the Width of intermediate transfer belt 9, makes that the second width position mark 382 that is formed on the photosensitive drums 1M overlaps on the first width position mark 381 that is formed on the photosensitive drums 1Y at first transfer printing portion TM place.Therefore, the aberration between yellow toner image for main scanning direction and the pinkish red toner image is eliminated.

Incidentally, be used to make the photosensitive drums 1M can also be by realizing with embodiment 3 described kindred organizations along the mechanism that the turning axle direction moves.

＜embodiment 8 〉

Figure 31 is the synoptic diagram of the used composition of the control among the demonstration embodiment 8.

In embodiment 8, by using the control of fixed pattern among the embodiment 4, on each sweep trace basis, the second color toner image that is carried on second image bearing member is superimposed on the first color toner image that is carried on the transfer member with respect to sub scanning direction.

In embodiment 8, by adopting among the embodiment 7 the second width position mark is positioned at control on the first width position mark by transfer member width position mark, the second color toner image that is carried on second image bearing member overlaps on the first color toner image that is carried on the transfer member with respect to main scanning direction.

Yet in embodiment 8, the first width position mark and the second width position mark are fixed as fixed pattern.Therefore other compositions and control similar to Example 7ly omit unnecessary explanation.

As shown in figure 31, on photosensitive drums 1Y, be set to fixed pattern in order to the primary importance mark 221 controlled with respect to sub scanning direction with in order to the first width position mark of controlling with respect to main scanning direction 381.On photosensitive drums 1M, the second width position mark 382 and be set to fixed pattern in order to the second place mark of controlling with respect to sub scanning direction 222.

At first transfer printing portion TY place, four sensors are set.These sensors are the reader 81Y that is used to detect primary importance mark 221, be used to detect the position transducer 71Y of the first width position mark 381, the position transducer 72Y that is used to detect the reader 82Y of transfer member position mark 251 and is used to detect transfer member width position mark 385.Yet as described in JP-A2004-29019, reader 81Y and position transducer 71Y can constitute individual unit, and reader 82Y and position transducer 72Y also can constitute individual unit.

At first transfer printing portion TM place, four sensors are set.These sensors are the reader 81M that is used to detect second place mark 222, be used to detect the position transducer 71M of the first width position mark 382, the position transducer 72M that is used to detect the reader 82M of transfer member position mark 251 and is used to detect transfer member width position mark 385.Similarly, reader 81M and position transducer 71M can constitute individual unit, and reader 82M and position transducer 72M also can constitute individual unit.

The reader 32Y that reader 81Y, 82Y, 81M and 82M are used to read corresponding fixed pattern and show with Figure 21 respectively, 39,32M is corresponding with 55.

Position transducer 71Y, 71M, 72Y and 72M are the sensor of describing among the embodiment 7.

The rotational speed of drive motor MM control photosensitive drums 1M by as shown in figure 21, the movement actuator 73M control intermediate transfer belt 9 by as shown in figure 24 is with respect to the position of Width.Therefore, with respect to main scanning direction and sub scanning direction control photosensitive drums 1M.

Then, carry out simultaneously, thereby prevent aberration for main scanning direction and sub scanning direction as embodiment 4 described processes with as embodiment 7 described processes.

＜embodiment 9 〉

Figure 32 is the synoptic diagram that shows the used second image bearing member travel mechanism of control among the embodiment 9, Figure 33 (a) and 33 (b) are the synoptic diagram that shows the correspondence that is carried on the image on the transfer member and second image bearing member respectively, Figure 34 shows the figure that concerns between the controlled quentity controlled variable of the velocity perturbation of transfer member and second image bearing member, and Figure 35 is the figure that shows the vibration of controlled quentity controlled variable under the controlled situation of the rotational speed of second image bearing member.

In embodiment 9, as described in embodiment 3, be used to make second image bearing member to be called another embodiment along the second image bearing member travel mechanism that the transfer member sense of rotation moves.The composition of imaging station PM, the rewriting between primary importance mark, second place mark and the transfer member position mark be with related, definite process of controlled quentity controlled variable etc. with partly in embodiment 1 and 3, describe identical.Therefore, with part consistent among the embodiment formerly by identical reference number or symbolic representation, therefore omit unnecessary explanation.

Shown in figure 32, the pinkish red toner image that is formed on the photosensitive drums 1M is sent to the first transfer printing TM of portion, and is transferred to for the first time on the intermediate transfer belt 9 by overlapping on the yellow toner image that is carried on the intermediate transfer belt 9.Be formed on the second place mark 222 on the photosensitive drums 1M and be formed on transfer member position mark 251 on the intermediate transfer belt 9 by use, pinkish red toner image is overlapped on the yellow toner image at first transfer printing portion TM place.

By by folding mirror 92 reflection lasering beam LM, exposure device 3M carries out scan exposure to the surface of photosensitive drums 1M, and described laser beam LM scans through rotary multi catoptron 91.Write the electrostatic image that is used for second place mark 222 that the electrostatic image that is used for image forms synchronously with utilizing laser beam LM scanning by developing apparatus (4M: Fig. 1) develop, thereby but provide the second place mark 222 of optical detection.That is to say that second place mark adjoining land is formed on the image bearing member.The reader 32M (as optical sensor) that is provided with by next-door neighbour before the first TM of transfer printing portion detects second place mark 222.

On the other hand, on intermediate transfer belt 9, form transfer member position mark 251, as reflection/absorption optical design.Detect transfer member position mark 251 by reader 35M (as optical sensor) for reader 32M apart from the first TM of transfer printing portion equidistant placement.

Second place mark and transfer member position mark 251 are reading near the position of the first TM of transfer printing portion, thus might from write electrostatic image up to pinkish red toner image arrive the first transfer printing TM of portion during, eliminate the velocity perturbation of photosensitive drums 1M.

Position correction control part 117 calculates departure between the respective scan line according to the testing result of the testing result of reader 32M and reader 35M.Then, position correction control part 117 carries out the position correction of photosensitive drums 1M, makes that the second image bearing member positional information of photosensitive drums 1M is consistent with the transfer member positional information of intermediate transfer belt 9, till corresponding sweep trace arrives the first transfer printing TM of portion.

Position correction control part 117 is measured first detection time of the transfer member position mark 251 that obtains by reader 35M and the mistiming between second detection time of the second place mark 222 that obtains by reader 32M.Then, position correction control part 117 is according to the controlled quentity controlled variable of this mistiming calculating location means for correcting 94.

The controlled quentity controlled variable actuated position means for correcting 94 of position correction control part 117 to calculate, thereby photosensitive drums 1M is moved along the sense of rotation of intermediate transfer belt 9, make corresponding second place mark 222 and corresponding transfer member position mark 251 arrive the first transfer printing TM of portion simultaneously.

Aforesaid process is intermittently carried out with the timing of for example per four sweep traces.Then, for photosensitive drums 1M, 1C and 1K, carry out similar process continuously and independently, make corresponding magenta, cyan and black toner image overlap on the yellow toner image, to prevent the aberration for sense of rotation.

Position correction apparatus 94 among the embodiment 9 is linear actuators, so that the photosensitive drums 1M in the photosensitive drums of intermediate transfer belt 9 is moved with fine pitch.As position correction apparatus 94, can preferably use device and have the device of the piezo-activator of applying piezoelectric effect with ultrasonic motor.

The left end of position correction apparatus 94 is fixed on the device housings 90, and right-hand member is fixed on the photosensitive drums supporting member.

Position correction apparatus 94 the symbol of position correction amount be timing laterally (level) enlarge and the corresponding length of position correction amount, the symbol of position correction amount when negative laterally (level) shrink and the corresponding length of position correction amount.

Photosensitive drums supporting member 93 integrally supports the moveable part that moves by position correction apparatus 94.Photosensitive drums 1M, charging device 2M, the developing apparatus that does not show, cleaning device and first transfer roll are connected on the photosensitive drums supporting member 93, thereby make the fluctuation of image-forming condition littler and make the variation of the first transfer printing TM of portion littler.

Photosensitive drums supporting member 93 is connected on the linear guides supporting member 96 movably by linear guides 95f and 95r.As shown in Figure 1, first transfer roll compress intermediate transfer belt 9 with the relative side of contact photosensitive drums that side of 1M, thereby between photosensitive drums 1M and intermediate transfer belt 9, form the first transfer printing TM of portion.

Incidentally, as described in embodiment 1, second place mark 222 can also only utilize exposure and form the potential pattern case, to replace the formation through exposure/developing process.In addition, can also by be provided with special-purpose writing station with second place mark 222 magnetic recordings in the magnetic recording layer of photosensitive drums 1M, perhaps after the light writing layer forms, write as the optical track in the CD.

Linear guides 95f and 95r are configured to slide by the rotation of inner bearing, but as another kind of method, also can adopt by use to have the structure that solid element or liquid than friction slide these guide rails.Linear guides supporting member 96 supports linear guides 95f and 95r, photosensitive drums supporting member 93 etc., makes it also can be directly connected on the device housings 90.

Here, suppose that transfer member position mark 251 forms at regular intervals, photosensitive drums 1M has complete circular cross section and is not having under the situation of excentricity with the Constant Angular Velocity rotation, and exposure device 3M forms second place mark 222 in the constant cycle.

Under this condition, under the immovable situation of intermediate transfer belt 9 speed, the detection of the transfer member position mark 251 that obtains by reader 35M regularly and the detection of the second place mark that obtains by reader 32M regularly synchronized with each other continuously.For this reason, after the position correction apparatus initial activation, do not carry out position correction.

Yet under the situation that the rotational speed of intermediate transfer belt 9 reduces, the detection that the detection of transfer member position mark 251 regularly is later than second place mark 222 regularly.Therefore, position correction control part 117 will be converted to based on the departure of the mistiming between detecting regularly apart from and with this apart from actuated position means for correcting 94.

Therefore, photosensitive drums 1M towards the upstream side shifting, makes the delay transfer member position mark 251 of intermediate transfer belt 9 sides and second place mark 222 arrive the first transfer printing TM of portion simultaneously with respect to the sense of rotation of intermediate transfer belt 9.

Shown in Figure 33 (a), end regions at intermediate transfer belt 9, transfer member position mark 251 and an initial point mark 250 are set, and described transfer member position mark 251 is the linear graduations that are arranged at intervals with mark with rule, and described initial point mark 250 indications are with respect to the initial point of circumferencial direction.Transfer member position mark 251 forms on the width of a sweep trace with the interval of per four sweep traces, and initial point mark 250 forms and is longer than transfer member position mark 251.Except the method that changes mark length, the initial point indicating means can also be method and the similar approach that changes method with respect to the width of circumferencial direction, changes distance between the adjacent mark.

Allocate in advance to calibration by incremental order since 1 numeral for initial point, and prefix is " M1-", so that distinguish mutually with scale (mark) numeral on the photosensitive drums 1M side.In Figure 33 (a), M1-4 distributes to the front end of the image that is formed by 32 sweep traces.Digital distribution can be at the photosensitive drums (1Y: Fig. 1) carry out carrying out during the transfer printing from being used for the first color toner image, subsequently, being used for the position control of the photosensitive drums of the second color toner image and follow-up color toner image can be according to carrying out at the number of division that carrying out from first photosensitive drums distributing during the transfer printing.In addition, after execution is used for the digital distribution of first photosensitive drums in advance, can also carry out the positioning control of each photosensitive drums.

Shown in Figure 33 (b), second place mark 222 is set in the end regions of photosensitive drums 1M, described second place mark 222 is for having the linear graduation of mark, and each mark is written into corresponding to a sweep trace of per four sweep traces location that writes during imaging.The corresponding scale of each of second place mark 222 (mark) numeral has prefix " M2-", so that other with the scale numeral phase region on intermediate transfer belt 9 sides.

Table 8 has shown the relation between the numeral that begins to distribute to the number of division of per four sweep traces and distribute to per four sweep traces by incremental order since first sweep trace from the initial point mark on the middle transfer belt 9 according to incremental order.

Table 8

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The line of image is counted the number of division on the number of division photosensitive drums on the band

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1 M1-4 M2-1

5 M1-5 M2-2

9 M1-6 M2-3

13 M1-7 M2-4

17 M1-8 M2-5

21 M1-9 M2-6

25 M1-10 M2-7

29 M1-11 M2-8

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With regard to first sweep trace of image, the number of division on intermediate transfer belt 9 sides is M1-4, and the number of division on the photosensitive drums 1M side is M2-1.

Each number of divisions process of position correction control part 117 preservations is closed on the reader 35M of the first transfer printing TM of portion location and time and the computing scale number of 32M.

Number of division on the intermediate transfer belt 9 is by the M1-1 that begins from initial point, M1-2 ... sequential counting and acquisition.Number of division on the photosensitive drums 1M side then is to count in such a way and obtain, and promptly makes at first detected calibration count M2-1, and calibration is subsequently counted M2-2, M2-3 ...

According to number of division that obtains above and elapsed time, position correction control part 117 calculates and is used to make the number of division for the same scan line numeral to pass through the required photosensitive drums 1M amount of movement of the first transfer printing TM of portion simultaneously.For example, be used for relevant photosensitive drums (1M, 1C by detection, 1K: (TK: Fig. 1) near departure comes executing location to proofread and correct for TM, TC in the first transfer printing of Fig. 1) each portion, even thereby when after short time exposure or velocity perturbation, velocity perturbation taking place, also can carry out overlapping correction.

Incidentally, with respect to using for the exposure device 3M of the rotatable polygonal mirror 91 of several ten thousand rev/mins high speed rotating, even when microvibration takes place, also can produce the analyzing spot deviation, make exposure device 3M be fixed on the device housings 90 by firm supporting member.

For this reason, during the position correction of photosensitive drums 1M, even when photosensitive drums 1M moves, exposure device 3M can not move yet.

Therefore, when photosensitive drums 1M is position correction when moving, the sweep trace and the second place mark 222 that are formed on the photosensitive drums 1M move on the surface of photosensitive drums 1M to change at interval.That is to say, change the scanning line density for sub scanning direction and the density of second place mark 222.

For example, under the situation that the speed of intermediate transfer belt 9 reduces, when photosensitive drums 1M moved to upstream side, the irradiation position of laser beam LM moved to upstream side with respect to the sense of rotation of photosensitive drums 1M.Therefore, the interval between the scale of the scale of the second place mark 222 of record and the current second place mark 222 that will write down increases in advance.

Thereafter, even the velocity perturbation elimination of intermediate transfer belt 9 and circular velocity aspect equal the circular velocity of photosensitive drums 1M, when the second place mark 222 that increases at interval arrives reader 32M, the interval that the detection constant time lag of second place mark 222 should increase.

Therefore, position correction control part 117 makes photosensitive drums 1M move towards the downstream with respect to the sense of rotation of intermediate transfer belt 9, so that catch up with the transfer member position mark 251 than the more Zao process of second place mark 222 that is positioned on intermediate transfer belt 9 sides.

Then, 1M moves to the downstream when photosensitive drums, and is opposite with the original position, and the irradiation position of laser beam LM moves towards the downstream with respect to the sense of rotation of photosensitive drums 1M, makes the interval of second place mark 222 to be recorded reduce.

Like this, the position correction amount of photosensitive drums 1M with influence the position correction amount of photosensitive drums 1M in the time of transfer printing in the corresponding cycle from exposing.

Then, under the velocity perturbation situation at random of intermediate transfer belt 9, the position correction amount of photosensitive drums 1M fluctuates as the center with 0, but under the situation that the speed of intermediate transfer belt 9 fluctuates in specific period, the maximal value of position correction amount increases and the range of control of setover correcting value in some cases in time.

As shown in figure 34, when the cycle of cycle of velocity perturbation and position correction amount overlapped each other, position correction amount added up to increase gradually, made that correction eventually can not the up-to-speed fluctuation.

Figure 34 has shown that the diameter at photosensitive drums 1M is 84mm, girth from the exposure position to the transfer position is 132mm, processing speed is 300mm/sec, and the velocity perturbation of intermediate transfer belt 9 is the analog result under the situation of ± 0.15% (doubling from exposing in the time of transfer printing time).In the drawings, horizontal ordinate is represented the position (mm) on the intermediate transfer belt 9, and the ordinate on the left side is represented the circular velocity (mm/sec) of intermediate transfer belt 9, and the ordinate on the right is represented position correction amount (μ m).

As shown in figure 34, the maximal value of the position correction amount of photosensitive drums 1M vibration is so that increase ± 42 μ m during the every rotation of photosensitive drums 1M 264mm.Particularly, maximal increment is ± 42 μ m in the scope of 0-264mm, is ± 84 μ m in the scope of 264-528mm, is ± 126 μ m in the scope of 528-792mm, is 168 μ m in the scope of 792-1056mm.

The velocity perturbation frequency f of the intermediate transfer belt 9 that causes by position correction amount vibration is represented by following equation:

f＝f0×(2×n-1)/2(n＝1，2，3...)

Wherein, f0 represents with from exposing to time of transfer printing frequency as one-period.

Figure 35 shown in as embodiment 1 Figure 32 form described in rotational speed by control photosensitive drums 1M make second place mark 222 overlap under the situation on the transfer member position mark 251 change of controlled quentity controlled variable aspect.

In this case, equal to simulate the position correction speed (m/sec) of photosensitive drums 1M by the velocity perturbation cycle that makes intermediate transfer belt 9 from exposing to the time of transfer printing.

In the figure, the ordinate on the horizontal ordinate and the left side is identical with Figure 34, and the ordinate on the right is represented position correction speed (circular velocity is with respect to the increase and decrease amount of processing speed) (mm/sec).

As shown in figure 35, the maximal value of the position correction amount of photosensitive drums 1M is vibrated, so that increase ± 0.15mm/sec during the every ROT13 2mm of photosensitive drums 1M.Particularly, maximal increment in the scope of 0-132mm is ± 0.15mm/sec, in the scope of 132-264mm be ± 0.30mm/sec, in the scope of 264-396mm be ± 0.45mm/sec, in the scope of 396-528mm be ± 0.60mm/sec, be ± 0.75mm/sec to be ± 0.9mm/sec in the scope of 528-660mm in the scope of 660-792mm.

The velocity perturbation frequency f of the intermediate transfer belt 9 that causes by the position correction velocity fluctuation is represented by following equation:

f＝f0×n(n＝1，2，3，...)

Wherein, f0 represents with from exposing to time of transfer printing frequency as one-period.

When in intermediate transfer belt 9, having the velocity perturbation of this periodicity (frequency f), be difficult to executing location and proofread and correct control, thereby it is desirable for when carrying out imaging on a sheet material, the motion of the irradiation position by making laser beam LM stops to come initialized location to proofread and correct.

Yet, proofread and correct for initialized location, be necessary between image, to be provided with the interval longer (being called sheet material at interval) than the distance from the exposure position to the transfer position.With regard to regard to the photosensitive drums 1M that uses in the above-mentioned simulation, the distance from the exposure position to the transfer position is 132mm, thereby is necessary the about 140mm that is spaced apart between the control chart picture.

Then, carrying out under the situation of continuous imaging under 100mm or the littler condition at interval between the image, when the interval between the image controls to about 140mm, but the decreased number of imaging sheet material in the time per unit.

＜embodiment 10 〉

Figure 36 is the synoptic diagram that shows the used second image bearing member travel mechanism of control among the embodiment 10, and Figure 37 is the time diagram of the control among the embodiment 10, and Figure 38 is the process flow diagram of the control among the embodiment 10, and Figure 39 is the process flow diagram of another control.

In embodiment 10, similar to Example 9, move and second place mark is positioned on the transfer member position mark along the transfer member moving direction by making second image bearing member.Therefore, in Figure 36, therefore the composition member identical with Figure 32 omit unnecessary explanation by identical reference number or symbolic representation.

In embodiment 10, as long as position correction amount exceeds preset range, continuous imaging is just carried out at interval with short, but when position correction amount departed from preset range, the regulated quantity of adjusting gear (regulating device) was set at initial value once more.

As shown in figure 36, position correction control part 118 compares estimated position (from the distance in original position) after the position correction with default permissible range ± 120 μ m, described estimated position adds that by giving position correction position before position correction amount obtains.Exceed in position correction (departure) estimated position afterwards+120 μ m or be lower than under the situation of-120 μ m, after the interval that makes follow-up imaging with about 140mm by control exposure device 3M is in standby condition to the position correction initialization.That is to say, surpass under the situation of predetermined value (being 120 μ m in this embodiment) at the absolute value of departure and carry out initialization operation.Alternatively, exceed in departure under the situation of preset range, carry out initialization operation.Therefore, the interval between the image makes the position correction initialization can not influence final image greater than the distance from the exposure position to the transfer position.

Initialization operation be meant make by control the sweep trace that changes aspect the irradiation position of laser beam LM from photosensitive drums 1M after the fully first transfer printing photosensitive drums 1M move to the original position.Here, the original position is meant the photosensitive drums 1M that has been determined in advance the initial position with respect to the throughput direction of intermediate transfer belt 9.By position correction control part 118 (initialization section) control initialization operation.

Shown in Figure 37 as reference Figure 36, exposure device 3M writes image continuously with the interval of distance L 2.Tracer signal is the signal that representation page (image) writes, and the transfer printing signal is the signal of representation page (image) transfer printing.

When the estimated position is lower than during in time T 1 when judging lower limit, position correction control part 118 is waited for finishing that second page writes, and carries out the wait of photosensitive drums 1M with distance L 3, and described distance L 3 is greater than the distance from the exposure position to the transfer position.Then, photosensitive drums 1M moves to original position (estimated position=0 after the position correction).

That is to say that when the writing of first page (exposure) beginning, first transfer printing begins after elapsed time L1.Time L1 is the time that arrives the first transfer printing TM of portion up to the exposure position of photosensitive drums 1M.

For first page, the estimated position maximal value after the position correction is in ± scope of 120 μ m within, make the record of second page carry out with the time L2 that is shorter than time L1.Yet, during time T 1 during the first transfer printing of second page, the estimated position after the position correction is lower than-120 μ m, makes position correction initialization when the time T 2 that the first transfer printing of second page is finished, when subsequently, the record of the 3rd page is from time T 3 (recovery).

In this case, the relation between the time L3 between the time L1 and second page, the 3rd page is set as follows:

L3>L1。

Shown in Figure 38 as reference Figure 36, position correction control part 118 during the start-of-record in position correction amount judged result register initial setting " OK " (S111), and the exposure control register in initial setting " ON " in case by exposure device 3M begin the exposure (S112).

Position correction control part 118 calculates (S113) process mistiming (S114) regularly when detecting transfer member position mark 251 and second place mark 222, and by described mistiming calculating location correcting value (S115).

Position correction control part 118 will compare (S118) according to estimated position and the judgment value scope that position correction amount be carried out after the position correction, and within the estimated position is in scope when (S118 " scope in ") execution as embodiment 9 described position corrections control (S119).

(exposure control register " ON ") control exposure device 3M when the estimated position of position correction control part 118 after position correction is within the judgment value scope is so that with short distance interval (L2: Figure 37) write image continuously.

When the estimated position after the position correction increases and departs from the judgment value scope (S118 " outside the scope "), position correction control part 118 is set " NG " (S120) in position correction amount judged result register.Then, exposure device 3M writes (S121 is a "No") and stops (S122) afterwards finishing image.This is because when stopping immediately when being written in imaging during, and image is stopping the interruption of part place.

(S121 is a "No") do not set " OFF " (S122) when position correction control part 118 was between exposure period at the page in the exposure control register, thereby prevented the exposure to subsequent page (image).

Position correction control part 118 is waited for finish (S123) of the first transfer printing that is formed on the image on the photosensitive drums 1M, subsequently the initialization operation (S124) proofreaied and correct of executing location.This is because during initialization immediately, can not be avoided the image deterioration at discontinuities place when position correction during imaging.Be at follow-up imaging operation under the situation of waiting status and carry out initialization operation.

After the position correction initialization was finished, the position correction control part recovered the record (from S111) of subsequent page.

Position correction apparatus 94 is according to carrying out the position correction of photosensitive drums 1M from the position correction amount of position correction control part 118, so that second place mark 222 is overlapped through on the transfer member 251 of the first transfer printing TM of portion.

Yet, in the position correction initialization (S124), position correction apparatus 94 is controlled so that photosensitive drums supporting member 93 moves, thereby is made photosensitive drums 1M turn back to the original position.

By repeating said process, finish the imaging on necessary number sheet material.

Incidentally, when in a single day the judged result of the estimated position after position correction went beyond the scope, the control of process flow diagram shown in Figure 38 was always carried out initialization to position correction after the transfer printing of related pages (image) is finished.

Yet the estimated position that the record of subsequent page (image) can also be after position correction was returned before the transfer printing of related pages (image) is finished under the situation in the scope and is begun.Figure 39 has shown the process flow diagram of this control.In Figure 39, the step identical with Figure 38 represented by identical reference symbol, therefore omits unnecessary explanation.

Shown in Figure 39 as reference Figure 36, when detecting transfer member position mark 251 and second place mark 222 (S113 " detecting "), position correction control part 118 calculating location correcting values (S115).

Position correction control part 118 in addition in the time between page exposure period in the time during (S121 is a "Yes") or the page transfer printing (S123 is a "Yes") position correction amount is judged for the estimated position after the position correction on basis.Then, when the estimated position after the position correction is returned within the scope (S118 " in the scope "), position correction amount judged result register becomes " OK " again (S131), thereafter, the exposure control register becomes " OK " again (S132), proofreaies and correct initialization (S124) in case stop bit is put.That is to say that as shown in figure 37, exposure device 3M writes image continuously with short distance interval L2.

Incidentally, in step S118, the judgment value when the judgement carried out from " outside the scope " to " in the scope " can be identical with the judgment value of using when the judgement carried out from " in the scope " to " outside the scope ".Yet by providing than being used for judging from " in the scope " to the little numerical value of the numerical value of " scope outside " (numerical value than close limit is provided), generation is repeatedly at short notice might to prevent " scope is interior " relevant with judged result and " outside the scope ".

In embodiment 10, when permissible range is departed from the estimated position after the position correction, position correction initialization initialization after the first transfer printing of the page is finished, and the position correction of the photosensitive drums 1M that carries out of use location means for correcting 94 is carried out continuously till the first transfer printing of the page is finished.For this reason, by providing surplus to be avoided position correction amount to exceed in position correction control part 118 is waited for the time that the first transfer printing of the pages finishes the situation of the control chart picture that can control by position correction apparatus 94 for the judgment value scope.

In fact, for example the velocity perturbation Frequency Design Cheng Buyu of the mechanical mechanism of gear etc. is overlapped by the frequency that position correction produces, make that position correction amount can not depart from the recoverable scope in the time of finishing since the first transfer printing that writes this page of a page.

At this, position correction apparatus 94 can be ± 200 μ m (upper limits=+ 200 μ m from the range of control of original position executing location control; Lower limit=-200 μ m).In addition, with regard to the judgment value scope, the judgment value that is used to judge is ± 120 μ m (upper limit=+ 120 μ m; Lower limit=-120 μ m).These numerical value are not the position correction amount of proofreading and correct with the time, but with the estimated position after the position correction of the distance expression in original position behind position correction apparatus 94 correction positions.

Therefore, position correction control part 118 compares the estimated position after the position correction with judging the upper limit+120 μ m and judgement lower limit-120 μ m.

As shown in figure 37, the increment of the estimated position after the position correction in a page is maximum ± 80 μ m.For this reason, in embodiment 10, the judgment value scope is ± 120 μ m, thereby with respect to the surplus that ± 80 μ m are set as the range of control ± 200 μ m of position-controllable system scope.

For example, after the 3rd page begins to expose, surpass under the situation of judgment value+120 μ m in the estimated position after the position correction immediately, even when position correction was proceeded till the first transfer printing of the 3rd page is finished, the estimated position after the position correction also was no more than+200 μ m.

Like this, by with respect to range of control, surplus being set, can carry out position control to judgment value.

In embodiment 10, judgment value is a fixed value, but also can be according to beginning elapsed time and be converted to numerical value near the range of control bound from writing beginning or transfer printing.That is to say that judgment value makes surplus reduce in time for what can change.

For example, judgment value changes, and makes the writing beginning and synchronously be set in ± 120 μ m (surplus=80 μ m) of judgment value and each page, and changes into when the first transfer printing of related pages is finished ± 200 μ m (surplus=0 μ m).Then, even during the first transfer printing of each page, the exposure of judgment value and subsequent page begins synchronously to get back to ± 120 μ m (surplus=80 μ m), changes similarly subsequently.

For this reason, judgment value is set in 120 μ m when the page writes beginning.Determine to write the time L5 that first transfer printing is finished, make that thereafter judgment value becomes with elapsed time, thereby is 200 μ m when the first transfer printing of related pages is finished since first page.

Incidentally, still carrying out under the situation about controlling, might be attended by the initialized similar control of control as the rotating speed of embodiment 1 described photosensitive drums 1M.

In this case, the initialization of speed control is meant, the sweep trace that changes aspect the irradiation position of laser beam LM carries out fully first transfer printing by control from photosensitive drums 1M, subsequently, be that the rotational speed of photosensitive drums 1M conforms to the rotational speed of intermediate transfer belt 9 under zero the situation in velocity perturbation.That is to say that the rotational speed of photosensitive drums 1M changes predetermined initial value into.

Then, the velocity contrast of the default speed of rotational speed is taken as the estimation rotating speed after rotational speed and the velocity correction, can compare with the judgement upper limit and the judgement lower limit that make default speed (initial value) as the center subsequently, the default speed of rotational speed adds that by giving velocity correction speed before the velocity correction amount obtains after the described velocity correction.

Then, after the velocity correction under the situation of estimated speed, write and be interrupted and correction initialization after first transfer printing is finished of speed control.

Therefore, surpass execution speed control initialization under the situation of permissible range, might realize effective continuous imagings, keep the short interval between the image simultaneously with a large amount of output sheet materials in the time per unit by the estimated speed velocity correction after only.When not carrying out initialization, imaging is carried out at interval continuously with short, thereby the reduction of the output sheet material quantity of image can not take place basically.Like this, might realize high image quality, the reduction of output sheet material quantity in the time per unit is minimized by reducing aberration.

＜embodiment 11 〉

Figure 40 shows that the pinkish red image among the embodiment 11 forms the synoptic diagram of the structure at station, and Figure 41 shows the figure that exposure device is fixed to the effect on the photosensitive drums supporting member.

In embodiment 11, similar to Example 9, the 3rd image bearing member moves along the moving direction of transfer member, so that second place mark is positioned on the transfer member position mark.Therefore, in Figure 40, the composition member identical with Figure 32 explained thereby omit by identical reference number or symbolic representation.

As shown in figure 40, in embodiment 11, electrostatic image 3M is fixed on the photosensitive drums supporting member 93, thereby whole mobile with photosensitive drums supporting member 93, thereby has eliminated in the composition shown in Figure 32 because the possible deviation of the exposure scanning position that position correction produces.

Shown in figure 32, in embodiment 9, exposure device 3M is fixed on the device housings 90.For this reason, even when position correction apparatus 94 moves photosensitive drums 1M by photosensitive drums supporting member 93, the position relation between photosensitive drums 1M and the exposure device 3M can not change.

Under the whole situation about moving of exposure device 3M and photosensitive drums 1M, in order to eliminate the vibration effect between moving period, photosensitive drums supporting member 93 firmly forms and compares with embodiment 9 has heavier weight.Be subjected to moving control so that move with micron/sub-micrometer precision under the situation of slight distance at this heavy photosensitive drums supporting member 93, piezo-activator is fit to do position correction apparatus 94.The maximum amount of movement of piezo-activator (being the linear actuators that utilizes piezoelectric effect) is little, but is characterised in that big load bearing capacity and macro position control.

By forming of embodiment 9 aberration amount to be solved be 200 μ m or still less, make that position correction apparatus 94 desired position correcting values also are 200 μ m or still less.For this reason, aspect the maximum amount of movement of piezo-activator weakness, do not having problems.

In Figure 40, use single piezo-activator, but can use two piezo-activators that are arranged opposite to each other, so that guarantee two-way high precision movement control.According to moving direction, two piezo-activators use or use simultaneously with switching mode, thereby can carry out small and high-precision mobile control.

As mentioned above, by using piezo-activator, might carry out photosensitive drums 1M and the position correction that is fixed with the heavy photosensitive drums supporting member 93 of exposure device 3M as position correction apparatus 94.

By the fixing position between photosensitive drums 1M and exposure device 3M relation, the scanning line density that photosensitive drums 1M goes up with respect to sub scanning direction can not change by position correction, makes always to write and carries out at interval with rule.

As shown in figure 41, in embodiment 11, might eliminate the vibration of position correction amount, and no matter the velocity perturbation frequency of intermediate transfer belt 9 how.Figure 41 be with Figure 34 the same terms under the analog result of position correction amount.Even when middle transfer belt 9 causes velocity perturbation, confirmed not have the vibrating dispersion of occurrence positions correcting value.

＜embodiment 12 〉

Figure 42 shows that the pinkish red image among the embodiment 12 forms the synoptic diagram of the composition at station.

In embodiment 12, similar to Example 9, second image bearing member moves along the moving direction of transfer member, so that second place mark is positioned on the transfer member position mark.Therefore, therefore the composition member identical with Figure 32 omit unnecessary explanation by identical reference number or symbolic representation.

In embodiment 1, exposure device 3M is fixed to photosensitive drums supporting member 93M and goes up moving with photosensitive drums 1M is whole, thereby has eliminated the influence of position correction to the interval (exposure density) that writes on the sweep trace on the photosensitive drums 1M.

As shown in figure 42, in embodiment 12, by operating the angle (attitude) that synchronously changes folding mirror (reflecting member) 92, eliminated in the composition shown in Figure 32 because the possible deviation of the exposure scanning position that position correction produces with the position correction of photosensitive drums 1M.

Folding mirror 92 is by two specularly reflected laser beam LM with reflecting surface, the extended line of described reflecting surface intersects at the rotating shaft center of folding mirror 92, thereby allows the position scan exposure on the photosensitive drums 1M identical with the situation of folding mirror 92 shown in Figure 32.

Folding mirror 92 as writing position mobile device example is supported in the present embodiment, thereby can regulate with the pitch angle of turning axle as the center by fixing two position relations between the mirror.For this reason, when the pitch angle of folding mirror 92 changed, the exposure scanning position moved when can remain on constant level (that is, focus condition does not change) at the optical path length of laser beam LM.

Utilize the piezo-activator of piezoelectric effect to wait with high precision by use and carry out minute angle control, mirror angle means for correcting (reflecting member mobile device) 98 changes the pitch angle (attitude) of folding mirror 92.

Position correction control part 119 control mirror angle means for correctings 98 pitch angle with adjusting folding mirror 92, thus elimination is by the sweep trace writing position amount of movement on the photosensitive drums 1M of the position correction generation of photosensitive drums 1M.That is to say that the attitude of reflecting member changes, so that follow the motion of photosensitive drums 1M.Therefore, sweep trace forms at interval near regular interval pitch.

That is to say that the pitch angle of folding mirror 92 is proofreaied and correct, even make that laser beam LM can not move the scan exposure position on photosensitive drums 1M yet when position correction apparatus 94 moves photosensitive drums 1M.

In embodiment 12, do not need to make exposure device 3M and photosensitive drums 1M integrally to move.Therefore, comprise that the driving weight of the position correction apparatus 94 of photosensitive drums supporting member 93 reduces, make and to proofread and correct with the high responsiveness executing location, eliminate the vibrating dispersion of position correction simultaneously.

＜embodiment 13 〉

Figure 49 has schematically shown the method that writes primary importance mark and second place mark by the laser beam flying exposure.

In embodiment 1, magnetic recording layer EY (EM) is formed on the photosensitive drums 1Y (1M), and primary importance mark 221 (second place mark 222) is recorded among the magnetic recording layer EY (EM).

In embodiment 3, by using exposure device 3Y (3M) and developing apparatus 4Y (4M), the primary importance mark 221 (second place mark 222) that is used for toner image writes on and is positioned at outside the lip-deep image-region of photosensitive drums 1Y (1M).

In embodiment 13, by using exposure device 3Y (3M), the primary importance mark 221 (second place mark 222) that is used for electrostatic image writes on and is positioned at beyond the lip-deep image-region of photosensitive drums 1Y (1M).

In embodiment 13, other compositions are identical with embodiment 1 basically, therefore omit explanation and unnecessary explanation.

As shown in figure 49, the laser beam LY that goes out from the light emitted of exposure device 3Y is by arriving the surface of photosensitive drums 1Y by rotatable mirror scanning, thus the sweep trace of the electrostatic image that is used for yellow image of drawing.Simultaneously, laser beam LM writes the electrostatic image that is used for primary importance mark 221, and it is as the outer sweep trace end of imaging region.

Primary importance mark 221 by make use up on the surface that writes on photosensitive drums (1M) and record as the surface electrical potential difference.

For reading and recording is the primary importance mark 221 of surface electrical potential difference, use surface potential sensor or its application apparatus as reader 32Y (32M).

As this sensor, for example can use the disclosed sensor of JP-A Hei 11-183542.

Still in this example, might use such method, wherein, the information that writes with about 100 μ m spacings is read, and subsequently, this positional information is divided by signal Processing.In order to read the 100 μ m pitch information that are formed in the primary importance mark 221, the conductor that it is desirable for the detection probe of reader 32Y (32M) has 100 μ m or littler diameter.

Incidentally, with embodiment 1 in identical method transfer member position mark 251 is recorded on the intermediate transfer belt 9.Each when detecting with sweep trace corresponding first location mark 221, writing station (34: Fig. 2) with transfer member position mark (251: Fig. 5) be recorded in the magnetic recording layer (E9: Fig. 5) of intermediate transfer belt 9.

As another kind of method, (4Y, 4M: Fig. 2) be attached on the electrostatic image, electrostatic image is converted to the visual information corresponding to the surface electrical potential difference, this visual information can be by optically read subsequently by developing apparatus for toner.

＜the second embodiment 〉

Figure 47 is the synoptic diagram that shows the composition of the imaging device among second embodiment.

Except using the recording materials transfer member to replace the intermediate transfer member, the composition of second embodiment is identical with first embodiment.Therefore, in Figure 47, the composition member identical with first embodiment be by identical reference number or symbolic representation, thereby omitted unnecessary explanation.

As shown in figure 47, the imaging device 200 of second embodiment is panchromatic laser beam printers, and wherein, the imaging station PY, PM, PC and the PK that are used for yellow, cyan, magenta and black arrange along recording materials conveying belt 9H.

At PY place, imaging station, yellow toner image is formed on the photosensitive drums 1Y, and is transferred to for the first time on the recording materials P that is carried on the recording materials conveying belt 9H.At PM place, imaging station, pinkish red toner image is formed on that photosensitive drums 1M goes up and is transferred to for the first time on the recording materials P by overlapping on the Yellow toner image.At imaging station PC and PK place, cyan toner image and black toner image are respectively formed on photosensitive drums 1C and the photosensitive drums 1K, and are transferred to similarly on the recording materials P with overlap mode.

, and rotate around driven roller 13 with jockey pulley 12 extends and by its support as the recording materials conveying belt 9H of transfer member example along direction shown in the arrow R2.

Recording materials P takes out from sheet feeding box 20 by sheet feeding roller 14, and separates one by one by tripping device 15, to flow to recording materials conveying belt 9H by registration roller 16.By after secondary transfer printing is to recording materials P, static is carried on recording materials P and the recording materials P electrostatic separation on the recording materials conveying belt 9H at four color toner images.

On it secondary transfer printing four kinds of color toner record images material P be transported to fixing device 17 and carry out hot pressing, make the full-colour image photographic fixing to the surface of recording materials P.

Still in the imaging device that uses this recording materials transfer member, might carry out composition and the control of embodiment 1 to 12.

The transfer member position mark is formed on the recording materials conveying belt 9H, and photosensitive drums 1M, 1C and 1K are controlled, and makes the second place mark that is formed on the photosensitive drums 1M overlap on the transfer member position mark at the first TM of transfer printing portion, TC and TK place respectively.

＜the three embodiment 〉

Figure 48 is the synoptic diagram that shows the composition of the imaging device among the 3rd embodiment.

Except being provided with along transfer member the single image bearing carrier, the composition of second embodiment is identical with first embodiment.Therefore, in Figure 47, the composition member identical with first embodiment be by identical reference number or symbolic representation, thereby omitted unnecessary explanation.

As shown in figure 48, the imaging device 300 among the 3rd embodiment is the panchromatic printer of single-drum type, wherein, arranges the single photosensitive drums 1 that can form a plurality of color toner images along intermediate transfer belt 9.Move towards photosensitive drums 1 by developing apparatus 4Y, 4M, 4C and the 4K that is used in yellow, magenta, cyan and black, rotary developing device 4 can form a plurality of color toner images.

The exposure device 3 that forms the device example as electrostatic image writes on electrostatic image on the photosensitive drums 1.

On the photosensitive drums 1 of rotation first lap, yellow toner image forms by using the Yellow toner as the first color toner example, is transferred to for the first time on the intermediate transfer belt 9 subsequently.

Pinkish red toner image is formed on the photosensitive drums 1 of rotation second circle by using the pinkish red toner as the second color toner example, is transferred to for the first time on the intermediate transfer belt 9 by overlapping on the yellow toner image subsequently.

The cyan toner image is formed on the photosensitive drums 1 of rotation the 3rd circle by using the cyan toner as the 3rd color toner example, is transferred to for the first time on the intermediate transfer belt 9 by overlapping on the pinkish red toner image subsequently.

Black toner image is formed on the photosensitive drums 1 of rotation the 4th circle by using the black toner as the 4th color toner example, is transferred to for the first time on the intermediate transfer belt 9 by overlapping on the cyan toner image subsequently.

Extend and by its support around driven roller 13, jockey pulley 12 and backing roll 10 as the intermediate transfer belt 9 of transfer member example, and rotate along direction shown in the arrow R2.

Four kinds of color toner images that are carried on the intermediate transfer belt 9 are transported to the T2 of secondary transfer printing portion, and at this place, the common secondary transfer printing of toner image is to recording materials P.Recording materials P takes out from sheet feeding box 20 by sheet feeding roller 14, and separates one by one by tripping device 15, to be fed into registration roller 16.

Registration roller 16 is fed into the T2 of secondary transfer printing portion with recording materials P, makes the front end of recording materials P overlap with toner image on the intermediate transfer belt 9.

On it secondary transfer printing four kinds of color toner record images material P be transported to fixing device 17 and carry out hot pressing, make the full-colour image photographic fixing to the surface of recording materials P.

Still in this single-drum type imaging device, might carry out composition and the control of embodiment 1 to 12.

The transfer member position mark is formed on the intermediate transfer belt 9, and the position mark that is formed on the photosensitive drums 1 is detected by the position mark pick-up unit.Then, photosensitive drums 1 is controlled, and makes position mark overlap on the transfer member position mark at first transfer printing portion T1 place.

Although the present invention is described with reference to structure disclosed herein, should not be limited to described details, the application is intended to contain and is included in the following claim scope or change or variation within the improvement purpose scope.

Claims (10)

1. imaging device comprises:

First image bearing member will form toner image on it;

Second image bearing member will form toner image on it;

Transfer member is in order to carrying and conveying toner image;

First transfer device is in order to be transferred to the toner image on described first image bearing member on the described transfer member at first transfer printing portion place;

Second transfer device, in order to the toner image on described second image bearing member is transferred on the described transfer member at second transfer printing portion place, the described second transfer printing portion is positioned at the downstream of the first transfer printing portion with respect to the moving direction of described transfer member;

The transfer member position mark, its moving direction along described transfer member is arranged on the described transfer member;

The image bearing member position mark, its sense of rotation along described second image bearing member is formed on described second image bearing member successively;

Transfer member position mark pick-up unit is in order to detect described transfer member position mark;

Image bearing member position mark pick-up unit is in order to detect described image bearing member position mark;

Regulating device is in order to the rotational speed of regulating described second image bearing member or described second image bearing member position with respect to described transfer member moving direction;

Controller, in order to control described regulating device, so that according to the testing result of described transfer member position mark pick-up unit and described image bearing member position mark pick-up unit, regulate the position of image bearing member position mark corresponding to the described transfer member position mark that will arrive the second transfer printing portion; With

Initialization section when exceeding preset range in order to the departure between described transfer member position mark and corresponding image bearing member position mark, is carried out the initialization operation of described regulating device.

2. imaging device as claimed in claim 1, wherein, described initialization operation comprises the operation of the regulated quantity that is used to set described regulating device.

3. imaging device as claimed in claim 1, wherein, described initialization operation is carried out under the waiting status of follow-up imaging operation.

4. imaging device as claimed in claim 3, wherein, described imaging device also comprises:

Exposure device is used so that described second image bearing member exposes to form electrostatic image; With

Developing apparatus makes electrostatic image development with the formation toner image in order to utilize toner,

Wherein, when not carrying out the operation of described exposure device, carry out described initialization operation.

5. imaging device comprises:

First image bearing member will form toner image on it;

Second image bearing member, the toner image that forms by the electrostatic image development that utilizes toner to make to be formed by exposure device will be carried on described second image bearing member;

Transfer member is in order to carrying and conveying toner image;

First transfer device is in order to be transferred to the toner image on described first image bearing member on the described transfer member at first transfer printing portion place;

Second transfer device, in order to the toner image on described second image bearing member is transferred on the described transfer member at second transfer printing portion place, the described second transfer printing portion is positioned at the downstream of the first transfer printing portion with respect to the moving direction of described transfer member;

The transfer member position mark, its moving direction along described transfer member is arranged on the described transfer member;

The image bearing member position mark, its sense of rotation along described second image bearing member is formed on described second image bearing member successively;

Transfer member position mark pick-up unit is in order to detect described transfer member position mark;

Image bearing member position mark pick-up unit is in order to detect described image bearing member position mark;

Regulating device is in order to regulate the position of described second image bearing member with respect to described transfer member moving direction;

Controller, in order to control described regulating device, so that according to the testing result of described transfer member position mark pick-up unit and described image bearing member position mark pick-up unit, regulate the position of image bearing member position mark corresponding to the described transfer member position mark that will arrive the second transfer printing portion; With

Supporting member in order to support described second image bearing member and exposure device, makes described second image bearing member and exposure device whole mobile.

6. imaging device comprises:

First image bearing member will form toner image on it;

Exposure device, it is provided with the reflecting member that is used for reflector laser;

Second image bearing member, the toner image that forms by the electrostatic image development that utilizes toner to make to be formed by second exposure device will be carried on described second image bearing member;

Transfer member is in order to carrying and conveying toner image;

First transfer device is in order to be transferred to the toner image on described first image bearing member on the described transfer member at first transfer printing portion place;

Second transfer device, in order to the toner image on described second image bearing member is transferred on the described transfer member at second transfer printing portion place, the described second transfer printing portion is positioned at the downstream of the first transfer printing portion with respect to the moving direction of described transfer member;

The transfer member position mark, its moving direction along described transfer member is arranged on the described transfer member;

The image bearing member position mark, its sense of rotation along described second image bearing member is formed on described second image bearing member successively;

Transfer member position mark pick-up unit is in order to detect described transfer member position mark;

Image bearing member position mark pick-up unit is in order to detect described image bearing member position mark;

Regulating device is in order to regulate the position of described second image bearing member with respect to described transfer member moving direction;

Controller, in order to control described regulating device, so that according to the testing result of described transfer member position mark pick-up unit and described image bearing member position mark pick-up unit, regulate the position of image bearing member position mark corresponding to the described transfer member position mark that will arrive the second transfer printing portion; With

The reflecting member mobile device in order to change attitude, makes that the exposure position of described exposure device is followed described second image bearing member when described second image bearing member is mobile under described regulating device effect.

7. imaging device comprises:

First image bearing member will form toner image on it;

Second image bearing member will form toner image on it;

Transfer member is in order to carrying and conveying toner image;

First transfer device is in order to be transferred to the toner image on described first image bearing member on the described transfer member at first transfer printing portion place;

Second transfer device, in order to the toner image on described second image bearing member is transferred on the described transfer member at second transfer printing portion place, the described second transfer printing portion is positioned at the downstream of the first transfer printing portion with respect to the moving direction of described transfer member;

The transfer member position mark, its along the moving direction fixed and arranged of described transfer member on described transfer member;

A plurality of image bearing member position marks, its along the sense of rotation fixed and arranged of described second image bearing member on described second image bearing member;

Transfer member position mark pick-up unit is in order to detect described transfer member position mark;

Image bearing member position mark pick-up unit is in order to detect described image bearing member position mark;

Regulating device is in order to regulate the rotational speed of described second image bearing member; With

Controller, in order to control described regulating device, so that according to the testing result of described transfer member position mark pick-up unit and described image bearing member position mark pick-up unit, regulate the position of image bearing member position mark corresponding to the described transfer member position mark that will arrive the second transfer printing portion.

8. imaging device as claimed in claim 7, wherein, when the position mark of transfer member at least in a pair of transfer member position mark that will control and the corresponding image bearing member position mark arrived moving direction with respect to described transfer member and is positioned at the precalculated position of the second transfer printing portion upstream, described controller was controlled another to transfer member position mark and image bearing member position mark.

9. imaging device as claimed in claim 7, wherein, when the position mark of image bearing member at least in a pair of transfer member position mark that will control and the corresponding image bearing member position mark arrived sense of rotation with respect to described second image bearing member and is positioned at the precalculated position of the second transfer printing portion upstream, described controller was controlled another to transfer member position mark and image bearing member position mark.

10. imaging device comprises:

First image bearing member will form toner image on it;

Second image bearing member will form toner image on it;

Transfer member is in order to carrying and conveying toner image;

First transfer device is in order to be transferred to the toner image on described first image bearing member on the described transfer member at first transfer printing portion place;

Second transfer device, in order to the toner image on described second image bearing member is transferred on the described transfer member at second transfer printing portion place, the described second transfer printing portion is positioned at the downstream of the first transfer printing portion with respect to the moving direction of described transfer member;

The transfer member position mark, its moving direction along described transfer member is arranged on the described transfer member;

A plurality of image bearing member position marks, its sense of rotation along described second image bearing member are arranged on described second image bearing member;

Transfer member position mark pick-up unit is in order to detect described transfer member position mark;

Image bearing member position mark pick-up unit is in order to detect described image bearing member position mark;

Regulating device is in order to regulate described second image bearing member with respect to the axial position of rotation; With

Controller, in order to control described regulating device, so that according to the testing result of described transfer member position mark pick-up unit and described image bearing member position mark pick-up unit, regulate the position of image bearing member position mark corresponding to the described transfer member position mark that will arrive the second transfer printing portion.

Images