CN101339379B - Image forming apparatus - Google Patents

Image forming apparatus Download PDF

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Publication number
CN101339379B
CN101339379B CN2008100929351A CN200810092935A CN101339379B CN 101339379 B CN101339379 B CN 101339379B CN 2008100929351 A CN2008100929351 A CN 2008100929351A CN 200810092935 A CN200810092935 A CN 200810092935A CN 101339379 B CN101339379 B CN 101339379B
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China
Prior art keywords
sheet material
image
speed
image taking
paper feed
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CN2008100929351A
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Chinese (zh)
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CN101339379A (en
Inventor
池田喜充
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Canon Inc
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Canon Inc
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Publication of CN101339379A publication Critical patent/CN101339379A/en
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/65—Apparatus which relate to the handling of copy material
    • G03G15/6555—Handling of sheet copy material taking place in a specific part of the copy material feeding path
    • G03G15/6558—Feeding path after the copy sheet preparation and up to the transfer point, e.g. registering; Deskewing; Correct timing of sheet feeding to the transfer point
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/65—Apparatus which relate to the handling of copy material
    • G03G15/6555—Handling of sheet copy material taking place in a specific part of the copy material feeding path
    • G03G15/6558—Feeding path after the copy sheet preparation and up to the transfer point, e.g. registering; Deskewing; Correct timing of sheet feeding to the transfer point
    • G03G15/6561—Feeding path after the copy sheet preparation and up to the transfer point, e.g. registering; Deskewing; Correct timing of sheet feeding to the transfer point for sheet registration
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/65—Apparatus which relate to the handling of copy material
    • G03G15/6555—Handling of sheet copy material taking place in a specific part of the copy material feeding path
    • G03G15/6558—Feeding path after the copy sheet preparation and up to the transfer point, e.g. registering; Deskewing; Correct timing of sheet feeding to the transfer point
    • G03G15/6561—Feeding path after the copy sheet preparation and up to the transfer point, e.g. registering; Deskewing; Correct timing of sheet feeding to the transfer point for sheet registration
    • G03G15/6564—Feeding path after the copy sheet preparation and up to the transfer point, e.g. registering; Deskewing; Correct timing of sheet feeding to the transfer point for sheet registration with correct timing of sheet feeding
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/00362—Apparatus for electrophotographic processes relating to the copy medium handling
    • G03G2215/00535—Stable handling of copy medium
    • G03G2215/00556—Control of copy medium feeding
    • G03G2215/00599—Timing, synchronisation
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/00362—Apparatus for electrophotographic processes relating to the copy medium handling
    • G03G2215/00919—Special copy medium handling apparatus
    • G03G2215/00945—Copy material feeding speed varied over the feed path

Abstract

The invention discloses an image forming apparatus capable of setting a plurality of image forming speeds. The image forming apparatus includes a transfer unit configured to transfer an image formed on an image carrier onto a sheet, a paper feed unit configured to feed the sheet, and a control unit configured to control the conveyance speed of the sheet to accelerate and decelerate without stopping the sheet in a section between the paper feed unit and the transfer unit to synchronize the sheet with the image formed on the image carrier. The control unit changes paper feed timing from the paper feed unit according to the image forming speed if the image forming speed is predetermined.

Description

Imaging device
Technical field
The present invention relates to a kind of imaging device such as laser printer or duplicating machine.More particularly, the present invention relates to the aiming at of sheet material and image in the intermediate transfer type imaging device, described imaging device began imaging operation before the paper feeding operation.
Background technology
At the traditional formation method that is used for such as the equipment of color laser printer or color copy machine, on as the single photosensitive-member of image-carrier, form in proper order by four kinds of color (Y: Huang, the toner of each M: magenta, C: green grass or young crops, K: black) and the image that forms.Be transferred to transfer member such as intermediate transfer element in proper order with above being superimposed upon by the image of photosensitive-member carrying, then, be transferred on the sheet material.The shortcoming of this method need to be considerable time to form complete coloured image on sheet material.
In recent years, developed have a plurality of photosensitive-members as image-carrier color laser printer to satisfy needs to higher image taking speed.In this color laser printer, optical device utilizes in a plurality of light beams each to scan the surface of each photosensitive-member independently to form the image of every kind of CMYK color.Coloured image is superimposed on the intermediate transfer belt, is transferred at last on the sheet material to form coloured image.This is called intermediate transfer system (below, be called tandem type).The tandem type laser printer uses a plurality of photosensitive-members to utilize multiple color (4 kinds of colors) to carry out imaging simultaneously.Therefore, compare, can significantly reduce the time that is used on sheet material, forming coloured image with said method.
The concrete configuration and the motion of tandem type laser printer then, are described with reference to Fig. 1.At first, to form electrostatic latent image, described photosensitive- member 13Y, 13M, 13C, 13K are recharged roller 15Y, 15M, 15C and 15K charging to the surface-emitting laser bundle of photosensitive- member 13Y, 13M, 13C and 13K for laser scanner 11Y, 11M, 11C and 11K.Then, developing cell 16Y, 16M, 16C and 16K impel toner to adhere to electrostatic latent image with image viewing.The toner order stack that adheres to photosensitive- member 13Y, 13M, 13C and 13K is added on the intermediate transfer belt 17 to form the color toner image.
On the other hand, in the moment of the toner image of sheet material 21 couplings on secondary transfer roll 29 place's intermediate transfer belts 17, feed rolls 25 is presented the sheet material 21 in the box 22.Then, conveying roller is transported to secondary transfer roll 29 to 27 with sheet material 21.By secondary transfer roll 29 the full color toner image on the intermediate transfer belt 17 is transferred to sheet material 21.By fixation unit 30 with the full color toner image to sheet material 21, and produce the full color printed matter.
Yet, when sheet material 21 and toner image on time because friction force between top-sheet and next sheet material or static etc. in the box 22, sheet material 21 is once in a while by two positions that separate roller 26a and 26b are set that supply to.In this case, the distance of the secondary transfer roll 29 that is transferred from sheet material 21 to image shortens, sometimes, before the image on the intermediate transfer belt 17 is transported to secondary transfer roll 29, the transfer position that sheet material 21 arrives on the secondary transfer roll 29.In addition, in some cases, the slip of feed rolls 25 makes sheet material 21 postpone, and the image on intermediate transfer belt 17 is transported to after the secondary transfer roll 29, and sheet material 21 arrives the transfer position at secondary transfer roll 29 places.These situations cause toner image and sheet material 21 misalignments.
In order to address this problem, for example, 11-249525 number open Japanese patent application of special permission discussed a kind of being used for no matter the sheet material of box two supply with or the slip of feed rolls and method that sheet material is aimed at toner image.
The conveying that Figure 10 illustrates sheet material 21 is stopped so that the example of the conventional art of aiming at toner image temporarily.Thick line among Figure 10 is the diagram of Y image, and described Y image is formed on the photosensitive drums of the upstream side that places intermediate transfer belt 17.The Y image is the yellow preimage that at first is transferred to intermediate transfer belt 17.Zone with perpendicular line shade shows the timing morning of presenting the timing ratio expectation of sheet material 21.More particularly, these zones show the position change of sheet material 21 when two supply of sheet material 21 occurring in box 22.On the other hand, the timing evening of presenting the timing ratio expectation that has the zone demonstration sheet material 21 of horizontal line shade.More particularly, these zones show the position change of sheet material 21 when the slip of feed rolls 25 occurring in box 22.
Usually, in use between in the tandem type of transfer belt 17, before paper feeding operation from box 22, the beginning imaging.When printing indication, begin imaging on each photosensitive-member according to order from Y image, M image, C image to the K image, the photosensitive-member of described Y image is positioned at the upstream side of intermediate transfer belt 17.Then, according to the order of Y, M, C and K, each image that forms on the corresponding photosensitive parts is transferred to intermediate transfer belt 17.Simultaneously, in the moment before forming toner image on the intermediate transfer belt 17, present sheet material 21 from box 22.
Carry the sheet material of presenting from box 22 21 by conveying roller to 27.When sensor 28 detected sheet material 21, the conveying of sheet material 21 stopped.Measure in advance from begin to detect the time of delivery of the sheet material 21 of sheet material 21 from the paper feeding of box 22 operation to sensor 28.Calculate the stand-by time of the conveying of sheet material 21 according to time of delivery.After the stand-by time of calculating, restart the conveying of sheet material 21.In this way, sheet material 21 is aimed at the toner image on the intermediate transfer belt 17, and perhaps, in other words, the forward position of sheet material 21 is aimed at the top of toner image.
According to the configuration of imaging device, stepping motor 45 is used to drive feed rolls 25 and conveying roller to 27, and described stepping motor 45 helps control position and speed in open-loop control system.Stepping motor 45 has following feature: if it was not restarted before the vibrations that produced by shut-down operation enough reduce, it is easy to imbalance.Therefore, stepping motor 45 needs relatively long stand-by time, significantly reduces up to vibrations.
Therefore, even under the situation that the shortest feed rolls of stand-by time 25 slides, the conveying of sheet material 21 also needs to stop, and significantly reduces up to the vibrations of stepping motor 45.If sheet material 21 stops the long time, then paper feeding increases and the handling capacity reduction at interval.In order not reduce the sheet material quantity of time per unit printing, need to increase processing speed.This can realize by the speed or the adjustment image-forming condition that increase stepping motor, yet this can increase cost or make control system become complicated.
Recently, under the situation that does not stop sheet material 21 sheet material 21 is being aimed at the toner image on the intermediate transfer belt 17.For example, this technology is discussed in the open Japanese patent application of 2004-333609 number special permission to some extent.Figure 11 illustrates the example that sheet material 21 is transported to the conventional art of its position of aiming at toner image continuously.As described in reference Figure 10, thick line is the diagram of Y image, and described Y image is formed on the photosensitive drums of the upstream side that places intermediate transfer belt 17.Zone with perpendicular line shade shows the timing morning of presenting the timing ratio expectation of sheet material 21.More particularly, these zones show the position of sheet material 21 when two supply of sheet material 21 occurring in box 22.In addition, the timing evening of presenting the timing ratio expectation that has the zone demonstration sheet material 21 of horizontal line shade.More particularly, these zones show the position of sheet material 21 when the slip of feed rolls 25 occurring in box 22.
When printing indication, begin imaging on each photosensitive-member according to order from Y image, M image, C image to the K image, the photosensitive-member of described Y image is positioned at the upstream side of intermediate transfer belt 17.Then, according to the order of Y, M, C and K, each image that forms on the corresponding photosensitive parts is transferred to intermediate transfer belt 17.Simultaneously, that aims at the top of toner image in the forward position of sheet material 21 is regularly desirable, presents sheet material 21 from box 22.To 27 feeding sheets 21, and detect sheet materials 21 by conveying roller by sensor 28.
Measure in advance from begin to detect the time of delivery of the sheet material 21 of sheet material 21 from the paper feeding of box 22 operation to sensor 28.According to time of delivery, the transporting velocity of sheet material 21 is quickened or slowed down, be transported to the predetermined control end point of the upstream that is positioned at secondary transfer roll 29 up to sheet material 21, in this control end point, sheet material 21 is aimed at toner image.When sheet material 21 is transported to the control end point, transporting velocity is reset to predetermined constant speed.This technology does not need to stop to drive feed rolls 25 and conveying roller to 27 stepping motor 45 temporarily, thereby helps to reduce paper feeding at interval and prevent the minimizing of handling capacity.In addition, this technology can improve printing efficiency, and can not increase processing speed.
In addition, imaging device can be provided with a plurality of processing speeds according to the type of sheet material 21.As everyone knows, the photographic fixing ability of sheet material 21 depends on its thickness, material and surface smoothness.For example, thick sheet is easy to absorb from fixation unit 30 than common sheet material or the sheet material thinner than thick sheet and more manys heat.Therefore, for fully melt toner and firmly with image fixing on thick sheet, thick sheet need be with slower speed by fixation unit 30.
In this case, can be by coming feeding sheets 21 with slower speed during by fixation unit 30 at sheet material 21, thus strengthen the photographic fixing of image.This technology is discussed in the open Japanese patent application of 6-208262 number special permission to some extent.Yet, according to the configuration of imaging device, not only can come feeding sheets 21, and can come feeding sheets 21 to 27 by secondary transfer roll 29 or conveying roller by fixation unit 30.Therefore, need to reduce the speed (transporting velocity of sheet material) of entire process that comprises image-generating unit but do not comprise the imaging device of fixation unit.
The open Japanese patent application of 11-249525 number special permission has been discussed a kind of being used for and has been quickened so that remedy the technology of time delay in paper feeding detection delay and with transporting velocity.In addition, the 2004-333609 Japanese patent application has been discussed the technology of the variation of a kind of pick-up time that is used to proofread and correct feed unit, by this technology, can present sheet material under the situation of the conveying that does not stop sheet material.
Yet above-mentioned traditional imaging device has following problem.
Using according to the type of sheet material under the situation of a plurality of processing speeds, the transporting velocity of sheet material 21 is accelerated or slows down, thereby under the situation of the conveying that does not stop sheet material 21, sheet material 21 is aimed at toner image.In this case, increased and driven feed rolls 25 and conveying roller speed setting range (scope that is provided with of driving frequency) 27 stepping motor 45.
For example, if the processing speed of thick sheet 21 is 1/4 of processing speeds (common process speed) of being used for common sheet material, then driving feed rolls 25 and conveying roller is 1000 pulse per seconds (pps) to the driving frequency of 27 stepping motor 45 for common sheet material, for thick sheet 21 is 250pps, in addition, if sheet material 21 being aimed at the change rate of necessary transporting velocity with toner image is ± 20%, then driving feed rolls 25 and conveying roller will be from 200pps to 1200pps to the scope of total driving frequency of 27 stepping motor 45, and this is quite wide scope.
Usually, stepping motor 45 is easy to produce vibrations and noise in than the driving of low velocity, and owing to the low torque in fair speed is lacked of proper care.If vibroshock or bigger stepping motor 45 are used to handle above-mentioned feature, then will increase the cost of imaging device.
Summary of the invention
The present invention is directed to a kind of can the conveying and also not increase under the motor condition of cost not stopping sheet material temporarily, the imaging device that sheet material is aimed at toner image.
More particularly, the present invention is directed to a kind of like this imaging device, the sheet material that it can be sent under the situation that does not temporarily stop the sheet material conveying, and can be under the situation of the big motor that does not add the vibrations that are used to reduce motor and the parts of noise or the speed setting range that use has broad, sheet material is aimed at toner image, thereby can be avoided the cost of imaging device to increase.
According to an aspect of the present invention, a kind of imaging device comprises: transfer printing unit is configured to and will be transferred on the sheet material at the image that forms on the image-carrier; And paper feed unit, be configured to and present sheet material, described equipment can be arranged on and form a plurality of image taking speeds that use in the process of image on the sheet material, the transporting velocity of sheet material is quickened and slowed down, and do not stop conveying in the section of sheet material between paper feed unit and transfer printing unit, thereby with sheet material and the image synchronization that forms on image-carrier, described equipment also comprises: supply unit, and the sheet material that is configured to present from paper feed unit is transported to transfer printing unit; And control module, be configured to control paper feeding timing from paper feed unit.If form image with first image taking speed (prestissimos in described a plurality of image taking speeds) or second image taking speed (in described a plurality of image taking speeds jogging speed), then the control module timing of presenting sheet material be different from when presenting sheet material with the image taking speed except first and second image taking speeds paper feeding regularly.
According to a further aspect in the invention, the imaging device that a plurality of image taking speeds can be set comprises: transfer printing unit is configured to and will be transferred on the sheet material at the image that forms on the image-carrier; Paper feed unit is configured to present sheet material; And control module, be configured to control the transporting velocity of sheet material so that quicken and slow down, and need in the section between paper feed unit and the transfer printing unit, do not stop sheet material, thereby with the image synchronization that forms on sheet material and the image-carrier.If image taking speed is scheduled to, then control module changes from the paper feeding of paper feed unit regularly according to described image taking speed.
Other characteristics of the present invention and aspect will become clear with reference to accompanying drawing to the detailed description of exemplary embodiment by following.
Description of drawings
The accompanying drawing that is incorporated in the instructions and constitutes an instructions part illustrates exemplary embodiment of the present invention, characteristics and each side, and it is used to explain principle of the present invention together with the description.
Fig. 1 illustrates the configured in one piece of tandem type color-image forming apparatus according to an exemplary embodiment of the present invention.
Fig. 2 illustrates the example alignment of sheet material and toner image according to an exemplary embodiment of the present invention.
Fig. 3 illustrates the exemplary configuration of control module according to an exemplary embodiment of the present invention.
Fig. 4 illustrates the example alignment of the sheet material and the toner image of first exemplary embodiment according to the present invention.
Fig. 5 illustrates the example alignment of the sheet material and the toner image of second exemplary embodiment according to the present invention.
Fig. 6 illustrates the example of the speed setting range of the alignment rolls of the 3rd exemplary embodiment according to the present invention and stepping motor.
Fig. 7 illustrates the example alignment of the sheet material and the toner image of the 4th exemplary embodiment according to the present invention.
Fig. 8 illustrates the example of the speed setting range of the alignment rolls of the 4th exemplary embodiment according to the present invention and stepping motor.
Fig. 9 illustrate the 4th exemplary embodiment according to the present invention stepping motor stop and printing efficiency between the example of relation.
Figure 10 illustrates by the conveying with sheet material and stops a period of time and exemplary conventional art that sheet material is aimed at toner image.
Figure 11 is illustrated in the exemplary conventional art of under the situation of the conveying that does not stop sheet material sheet material being aimed at toner image.
Embodiment
Describe each exemplary embodiment of the present invention, characteristics and aspect below with reference to accompanying drawings in detail.
First exemplary embodiment
Fig. 1 illustrates the configured in one piece of the tandem type color-image forming apparatus of first exemplary embodiment according to the present invention.The configuration of imaging device at first, is described with reference to Fig. 1.
The tandem type color-image forming apparatus is configured to by stack by yellow (Y), pinkish red (M), blue or green (C) with deceive the image that the toner of (K) four kinds of colors forms and export full-color image.The tandem type color-image forming apparatus comprises: laser scanner 11Y, 11M, 11C and 11K and the imaging box 12Y, 12M, 12C and the 12K that are used for coming according to every kind of color imaging.Imaging box 12Y, 12M, 12C and 12K comprise: photosensitive- member 13Y, 13M, 13C and 13K, and it is according to the direction rotation of the arrow of Fig. 1; Photosensitive-member clearer 14Y, 14M, 14C and 14K, its contact photosensitive- member 13Y, 13M, 13C and 13K; Charging roller 15Y, 15M, 15C and 15K; And developing cell 16Y, 16M, 16C and 16K.
In addition, among photosensitive- member 13Y, 13M, 13C and the 13K each is set to contact with intermediate transfer belt 17, and each among primary transfer roller 18Y, 18M, 18C and the 18K is arranged on the intermediate transfer belt 17 towards the position of each of photosensitive- member 13Y, 13M, 13C and 13K.In addition, at the band clearer 19 that is provided for reclaiming the toner that remains on the intermediate transfer belt 17 on the intermediate transfer belt 17.The used toner that also provides used toner storehouse 20 to collect by band clearer 19 with storage.
The box 22 that is used to store sheet material 21 comprises: guide piece 23, with the position limit of sheet material 21 in box 22; Paper detection sensor 24 detects the existence of sheet material 21 in box 22.Along the transport path of sheet material 21 be provided with feed rolls 25, separate roller to 26a and 26b and conveying roller to 27.On the paper throughput direction, on the downstream, sensor 28 is set near to 27 at conveying roller.Secondary transfer roll 29 orientated as with intermediate transfer belt 17 contact.Level after secondary transfer roll 29 is provided with fixation unit 30.Among laser scanner 11Y, 11M, 11C and the 11K each comprises the parts such as Laser emission element and polygonal mirror (not shown).Because these parts have known configuration, therefore will omit description of them.
Then, will describe electrofax handles.At first, by among charging roller 15Y, 15M, 15C and the 15K in each of imaging box 12Y, 12M, 12C and 12K each uniform charging is carried out on each the surface among photosensitive- member 13Y, 13M, 13C and the 13K.Then, laser scanner 11Y, 11M, 11C and 11K utilize according to the laser beam of view data modulation and shine each surface among photosensitive- member 13Y, 13M, 13C and the 13K.Form electrostatic latent image on each the surf zone of photosensitive- member 13Y, 13M, 13C and 13K, this is because laser beam has been removed with the electric charge on the part of its irradiation.Among developing cell 16Y, 16M, 16C and the 16K each impels the toner of charging to adhere to the electrostatic latent image that forms on each the surface of photosensitive- member 13Y, 13M, 13C and 13K, to form the toner image of every kind of color on each the surface of photosensitive- member 13Y, 13M, 13C and 13K.In addition, be transferred to intermediate transfer belt 17 by primary transfer roller 18Y, 18M, 18C and 18K according to the toner image that the mode of stack will form on each the surface of photosensitive- member 13Y, 13M, 13C and 13K.
Above-mentioned laser scanner, photosensitive-member, charging roller and developing cell constitute the image-generating unit of color-image forming apparatus.Photosensitive-member is charged with predetermined potential by charging roller, form sub-image by laser scanner.By developing cell sub-image is developed, and on photosensitive-member, form image.
On the other hand, present sheet material 21 in the box 22 by feed rolls 25.Even present multipage sheet material 21, also have only one page sheet material 26a and 26b to be transported to conveying roller to 27 by separate roller from box 22.Then, by secondary transfer roll 29 toner image on the intermediate transfer belt 17 is transferred on the sheet material 21.At last, the toner image on the sheet material 21 is by fixation unit 30 photographic fixing, and is discharged to the outside of imaging device.
Then, with reference to Fig. 1 and Fig. 2 aiming at of toner image and sheet material 21 described.Fig. 2 illustrates aiming at of sheet material 21 and toner image.Here, only be described among the imaging box 12Y imaging regularly and the conveying of sheet material 21 regularly.By secondary transfer roll 29 highest distance position that toner image is transferred to sheet material 21 is arranged to picture box 12Y in distance.To omit description to residue imaging box (12M, 12C, 12K).
Z-axis representative among Fig. 2 is transferred to the paper position of sheet material from carrying beginning by transfer roll up to toner image.The sheet material 21 that the position display of box rear end is provided with in box on the Z-axis is at the trailing edge of throughput direction.In addition, in Fig. 1, some A is used to begin the point that image writes, and some B is the control end point.The pressing of separate roller 26a and 26b part, conveying roller to 27, the location of sensor 28 and secondary transfer roll as shown in Figure 1.Transverse axis among Fig. 2 is represented the time.
In Fig. 2, paper feeding is defined as at interval from first sheet material is transported to separate roller is transported to the pressing part up to next sheet material to the pressing of 26a and 26b part time.In addition, according to this exemplary embodiment, before the conveying of beginning sheet material, the beginning image writes, and before presenting sheet material from box, forms toner image on intermediate transfer belt 17.Therefore, carry out aiming at of paper and toner image synchronously by control time of presenting of paper and transporting velocity and with toner image and sheet material.
Distance L d and angular velocity Vd based on photosensitive-member 13Y determine that image has the position of the photosensitive-member 13Y of laser to be transferred to the transfer printing time of primary transfer roller 18Y from irradiation.Distance L d is the illuminated laser spot of photosensitive-member 13Y and the distance between the primary transfer roller 18Y.In addition, the time T d that moves on photosensitive-member 13Y of image will be Ld/Vd.Determine to transfer images to intermediate transfer belt 17 run duration (run duration Tb) of image afterwards based on distance L d and actuating speed Vb by primary transfer roller 18Y.Distance L b is the distance between primary transfer roller 18Y and the following transfer position, and in described transfer position, image is by secondary transfer roll 29 transfer printings.Actuating speed Vb is the superficial velocity of intermediate transfer belt 17.The run duration Tb of image will be Lb/Vb.
The time of delivery of sheet material 21 from box 22 to following transfer position will be the following summation that is used for the time of delivery of each conveyor zones, and in described transfer position, image is by secondary transfer roll 29 transfer printings.The superficial velocity Vb of intermediate transfer belt 17 is counted as the processing speed Vb among the present invention usually.In Fig. 2, the transporting velocity of sheet material 21 is counted as the speed identical with processing speed Vb.Time of delivery Tp is that 22 rear end is fed the time that is transported to following transfer position up to sheet material 21 along the sheet material throughput direction from box from sheet material 21, and in described transfer position, image is by secondary transfer roll 29 transfer printings.Time T p will be (L1+Lf+Lc+Lr)/Vb, wherein, Ll is a box 22 along the rear end of sheet material throughput direction and separate roller to the distance between the pressing part of 26a and 26b, Lf is a separate roller to the pressing part of 26a and 26b and the distance between the sensor 28, and Lc+Lr is the distance between sensor 28 and the secondary transfer roll 29.
Therefore, by beginning Td+Tb-Tp=Tg begins sheet material 21 after the time conveying from imaging, sheet material 21 is aimed at toner image.Time representation between the conveying of the beginning of imaging and sheet material 21 begun is Tg.Distance L c is with lower curtate, and at described section, the speed of sheet material 21 is Be Controlled after sheet material 21 is by sensor 28.At section Lc, can quicken or slow down the speed of sheet material 21.Section Lr after section Lc, speed that need sheet material 21 is set to the speed identical with the superficial velocity Vb of intermediate transfer belt 17.Fig. 2 illustrates when slip does not all take place with two supplies, the relation of toner image and sheet material 21.
Then, with reference to Fig. 1, Fig. 3 and Fig. 4, according to the present invention first exemplary embodiment describe with as the processing speed Vbmax of the maximum available processes speed of imaging device to the position of toner image and the aligning control of sheet material 21.Fig. 3 illustrates the configuration of control module 41.Sensor 28 is connected to measuring unit 42.Measuring unit 42 measure sheet materials 21 from box 22 to sensor 28 time of delivery.Measuring unit 42 is connected to computing unit 43.According to the measurement result that obtains from measuring unit 42, computing unit 43 calculates feed rolls 25 and conveying roller to 27 optimal transport speed, and result of calculation outputed to drives feed rolls 25 and the conveying roller driving circuit 44 to 27 stepping motor 45.
Fig. 4 illustrates when the processing speed of imaging equipment is maximum processing speed, and sheet material 21 is aimed at the toner image that forms on intermediate transfer belt 17.Thick line among Fig. 4 is the diagram of Y image, and described Y image is formed on the photosensitive drums of the upstream side that places intermediate transfer belt 17.Zone with perpendicular line shade shows timing (see figure 2) morning of presenting the timing ratio expectation of sheet material 21.More particularly, these zones show when two supply of sheet material 21 occurring in box 22, the position change of sheet material 21.On the other hand, the timing (see figure 2) in evening of presenting the timing ratio expectation that has the zone demonstration sheet material 21 of horizontal line shade.More particularly, these zones show when the slip of feed rolls 25 occurring in box 22, the position change of sheet material 21.
At first, will the basic operation of the conveying of sheet material 21 be described.According to the speed identical, will be transported to sensor 28 from the sheet material 21 that box 22 is presented with the superficial velocity Vb of intermediate transfer belt 17.Simultaneously, measuring unit 42 is measured sheet material 21 is transported to sensor 28 from box 22 time.According to the measurement result of measuring unit 42, in speed control section Lc (sensor 28 and control end position between) feeding sheets 21, control feed rolls 25 and conveying roller be to 27 speed, thereby sheet material 21 is aimed at toner image.After sheet material 21 is by the control end position, the speed of sheet material 21 is adjusted into the speed identical with the superficial velocity Vbmax of intermediate transfer belt 17.
Then, will describe in detail according to as the processing speed Vbmax of the maximum processing speed of imaging device aiming at sheet material 21 and toner image.When photosensitive-member 13Y begins imaging,, present sheet material 21 from box 22 in time than the Zao α of time T g.As mentioned above, time T g is the time that begins to the conveying of sheet material 21 of beginning from imaging.In other words, begun the conveying of sheet material 21 according to arriving described image by the timing of the transfer position of secondary transfer roll 29 transfer printings from box 22 at time sheet material 21 than the Zao α of toner image.Here, time T s is the maximum acceptable paper transportation lag time.Described delay is caused by the slip of feed rolls 25 in the box 22.In addition, slide accordingly if take place can to accept time T s with maximum, then by measuring unit 42 sheet material 21 being sent to the time measurement that sensor 28 spent from box 22 is that the time T s of duration does not take place than sliding.Therefore, need adjust time T s at speed control section Lc, described speed control section Lc is the section between sensor 28 and the control end position.
Yet, because the delivery ratio toner image leading time α of sheet material 21, will be Ts-α required correction time so sheet material 21 aimed at toner image.If the common transporting velocity among the speed control section Lc is Vb, then the time of delivery among the section Lc will be Lc/Vb, in order to remedy Ts-α time delay, need come feeding sheets 21 along speed control section Lc at time (Lc/Vbmax)-(Ts-α).Obtain transporting velocity by following equation (1) thus.
Transporting velocity=(Vbmax * Lc)/((Lc-Vbmax * (Ts-α)) ... (1)
Here, by time α being arranged within the scope of 0＜α≤Ts, can reduce the speed adjustment of in speed control section Lc, arriving acceleration side.In addition, when α=Ts, it is minimum that the speed adjustment becomes, and for processing speed Vbmax, it is unnecessary to quicken.
When imaging on common sheet material, be the maximum processing speed of imaging device according to the maximum processing speed Vbmax of this exemplary embodiment.Imaging device according to this exemplary embodiment can be provided with the processing speed that is lower than processing speed Vbmax.For example, under the processed situation of thick sheet (than common sheet material thick or than the more sheet material of common sheet material grammes per square metre), processing speed be reduced to processing speed Vbmax speed 1/2.In addition, under the processed situation of light facesheet (having higher other sheet material of gloss level than common sheet material), processing speed be reduced to processing speed Vbmax speed 3/4.
When processing speed be processing speed Vbmax speed 1/2 or 3/4 the time, the time at aforesaid morning of α, do not begin the paper feeding of sheet material 21.In other words, if in processing speed be processing speed Vbmax speed 1/2 or 3/4 o'clock sheet material 21 paper feeding begin be counted as with reference to regularly, then this exemplary embodiment is characterised in that than with reference to regularly the time of Zao α is beginning the paper feeding of sheet material.
In addition, in Fig. 4, if transporting velocity needs tangible adjustment amount, then when sheet material 21 arrives sensor 28 and when it arrives the control end point, the transporting velocity of sheet material 21 obviously changes.If the change of transporting velocity is obvious, the imbalance of stepping motor 45 then can take place.According to this exemplary embodiment, the speed control of stepping motor 45 for quickening gradually or slowing down, can be avoided imbalance thus.Owing to when sheet material is transported to the control end point from sensor 28, the speed inhibition of acceleration and the speed of slowing down are set, to recover Ts-α time delay, so can obtain to be similar to the effect of obvious change speed.Because the acceleration of stepping motor 45 that can be by exemplary embodiment described below obtains to be similar to the effect when transporting velocity changes fast, so will omit the description of the effect of stepping motor 45.
According to this exemplary embodiment, can minimize the rate of growth of the transporting velocity of sheet material 21.Therefore, realize aiming at of sheet material 21 and toner image, prevent from simultaneously to drive feed rolls 25 and conveying roller to 27 stepping motor 45 owing to the imbalance that causes in high speed range minimizing torque, in addition, do not need to increase the size of stepping motor 45 yet.
Second exemplary embodiment
According to second exemplary embodiment, when the processing speed of imaging equipment was minimum treat speed Vbmin, control sheet material 21 was aimed at toner image.Although describe second exemplary embodiment,, therefore omit description of them owing in first exemplary embodiment, described Fig. 1 and Fig. 3 with reference to Fig. 1, Fig. 3 and Fig. 5.Fig. 5 illustrates when the processing speed of imaging equipment is minimum treat speed Vbmin, and sheet material 21 is aimed at toner image.
Thick line among Fig. 5 is the diagram of Y image, and described Y image is formed on the photosensitive drums of the upstream side that places intermediate transfer belt 17.Zone with line shade shows timing (see figure 2) morning of presenting the timing ratio expectation of sheet material 21.More particularly, these zones show when two supply of sheet material 21 occurring in box 22, the position change of sheet material 21.On the other hand, the timing (see figure 2) in evening of presenting the timing ratio expectation that has the zone demonstration sheet material 21 of horizontal line shade.More particularly, these zones show when the slip of feed rolls 25 occurring in box 22, the position change of sheet material 21.
When photosensitive-member 13Y begins imaging,, present sheet material 21 from box 22 in time than the late β of time T g.Time T g is the time that begins to the conveying of sheet material 21 of beginning from imaging.In other words, begun the conveying of sheet material 21 according to arriving described image by the timing of the transfer position of secondary transfer roll 29 transfer printings from box 22 at time sheet material 21 than the late β of toner image.Here, distance L l is two ultimate ranges of supplying with in the box 22, and just box 22 is in the end points of paper throughput direction and the distance between separate roller 26a and the 26b.Two supplies are a kind of like this phenomenons: the uppermost sheet material in the box and next sheet material are carried simultaneously.
If with ultimate range two the supply taken place, then sheet material 21 is sent to time that sensor 28 spent with as described below from box 22.
If sheet material 21 is and the identical speed of minimum treat speed Vbmin then will measure sheet material 21 by measuring unit 42 than the time of feeding sheets 21 Zao Ll/Vbmin under the situations that do not have two supplies in the transporting velocity of section L1.Therefore, need among speed control section Lc, adjust the time that equals Ll/Vbmin as section from sensor 28 to the control end position.
Yet because toner image is than 21 leading time of sheet material β, the required time of adjustment that is used for sheet material 21 is aimed at toner image will be Ll/Vbmin-β.If the common transporting velocity at speed control section Lc is Vbmin, then the time of delivery at section Lc will be Lc/Vbmin.Therefore, in order to adjust time Ll/Vbmin-β at section Lc, need be in time (Lc/Vbmin)+(Ll/Vbmin-β), at speed control section Lc feeding sheets 21.Therefore, obtain transporting velocity by following equation (2).
Transporting velocity=(Vbmin * Lc)/(Lc+Ll-Vbmin * β) ... (2)
Here, in the scope that time β is arranged on 0＜β≤(Ll/Vbmin), can reduce the speed adjustment of deceleration side in speed control section Lc.In addition, when β=Ll/Vbmin, it is minimum that the speed adjustment becomes, and for processing speed Vbmin, needn't slow down.
When processing speed be maximum processing speed Vbmax (in first exemplary embodiment, describing) speed 1/2 or 3/4 the time, as mentioned above, in the time of late β, do not begin the paper feeding of sheet material 21.In other words, if when processing speed be maximum processing speed Vbmax speed 1/2 or 3/4 the time sheet material 21 paper feeding begin be counted as with reference to regularly, then this exemplary embodiment is characterised in that than with reference to regularly the time of late β is beginning the paper feeding of sheet material.
According to this exemplary embodiment, can minimize feed rolls 25 and conveying roller reduced rate to 27 transporting velocity.Therefore, can be in the low velocity zone, be used to drive under feed rolls 25 and conveying roller the situation not producing to the vibrations of 27 stepping motor 45 and noise, realize aiming at of sheet material 21 and toner image, and can avoid using vibroshock.
The 3rd exemplary embodiment
In the 3rd exemplary embodiment, if the speed of imaging device is the maximal rate of a plurality of processing speeds, then presenting sheet material, and will move to deceleration side by the scope of the speed of the control module control of the transporting velocity of sheet material 21 being quickened or being slowed down in timing early.On the other hand,, then present sheet material, and will move to acceleration side by the scope of the speed of the control module that the transporting velocity of sheet material 21 quickened or slowed down control in later timing if the speed of imaging device is the minimum speed of a plurality of processing speeds.That is to say that the control to the paper feeding timing in the 3rd exemplary embodiment is the combination of first and second exemplary embodiments.
Owing in first and second exemplary embodiments, describe in detail, so will omit description to these controls with the aiming at of maximum processing speed Vbmax and minimum treat speed Vbmin control sheet material 21 and toner image.
According to this exemplary embodiment, maximum processing speed Vbmax is 200mm/s, and minimum treat speed Vbmin is 50mm/s.When processing speed was maximum processing speed Vbmax, the driving frequency of stepping motor 45 was 1000pps.When processing speed was minimum treat speed Vbmin, the driving frequency of stepping motor 45 was 250pps.Speed control section Lc is 120mm, and it is 100ms that the maximum that is caused by the slip of feed rolls 25 in the box 22 can be accepted paper transportation lag time T s, and two ultimate range Ll that supply with of sheet material 21 are 30mm.In addition, if the paper feeding of sheet material 21 regularly is set to than being the Zao time α of timing of maximum processing speed Vbmax when processing speed, then will (Vbmax * Lc)/((Lc-Vbmax * (Ts-α)) obtains to be used to adjust the transporting velocity that maximum can be accepted time T s by equation.Described equation is identical with equation (1) in first exemplary embodiment.Similarly, if the paper feeding of sheet material 21 regularly is set to the reference late time β regularly when when processing speed being minimum treat speed Vbmin, then will (Vbmin * Lc)/(Lc+Ll-Vbmin * β) obtains to be used to adjust pair transporting velocity of the ultimate range Ll of supply by equation.Described equation is identical with equation (2) in second exemplary embodiment.
Fig. 6 illustrates for sheet material 21 is aimed at toner image, when a plurality of processing speeds comprise feed rolls 25 and conveying roller to 27 acceleration or when slowing down, feed rolls 25, conveying roller are to 27 and drive feed rolls 25 and the conveying roller speed setting range to 27 stepping motor 45.From table, save at the deceleration adjusted value of maximum processing speed with at the acceleration adjusted value of minimum treat speed, because these values can not influence feed rolls 25, conveying roller to 27 with drive the speed setting range of the stepping motor 45 of described roller 25 and 27.In other words, if processing speed is such as 1/2 or 3/4 of the speed of the maximum processing speed Vbmax that describes in first and second exemplary embodiments, then since can be within the scope of 50-200mm/s control rate, so, carry regularly also needn't change even take place to slide or two supply.
Table (a) illustrates when α=β=0ms or under the situation that not have to implement in this exemplary embodiment, feed rolls 25, conveying roller to 27 and driving feed rolls 25 and conveying roller to the speed setting range of 27 stepping motor 45.Be that the conveying of sheet material does not regularly change under 1/2 or 3/4 the situation of speed of maximum processing speed Vbmax in processing speed.In this case, feed rolls 25 and conveying roller will be 40-240mm/s to 27 transporting velocity, drive feed rolls 25 and conveying roller and will be 200-1200pps to the driving frequency of 27 stepping motor 45.
Table (b) is illustrated under the situation according to this exemplary embodiment α=50ms and β=300ms, and feed rolls 25, conveying roller are to 27 and drive feed rolls 25 and the conveying roller speed setting range to 27 stepping motor 45.In this case, feed rolls 25 and conveying roller will be 44-218mm/s to 27 transporting velocity, drive feed rolls 25 and conveying roller and will be 222-1091pps to the driving frequency of 27 stepping motor 45.
Table (c) is illustrated under the situation according to the α=100ms of this exemplary embodiment and β=600ms, and feed rolls 25, conveying roller are to 27 and drive described roller 25 and the conveying roller minimum speed setting range to 27 stepping motor 45.In this case, feed rolls 25 and conveying roller will be 50-200mm/s to 27 transporting velocity, drive feed rolls 25 and conveying roller and will be 250-1000pps to the driving frequency of 27 stepping motor 45.
As mentioned above, the beginning of the conveying by changing sheet material when maximum or the minimum treat speed operation imaging device regularly, speed setting range that can stepping motor 45 is set to be similar to or equal the scope of 50-200mm/s.
According to this exemplary embodiment, can narrow down driving feed rolls 25 and conveying roller scope to the driving frequency of 27 stepping motor 45.Therefore, can be under the situation that does not reduce printing efficiency, conveying roller 25 and the conveying roller scope to 27 transporting velocity is minimized.Therefore, can do not cause stepping motor 45 owing to the situation that reduces the imbalance that torque causes in high speed range under, realize aiming at of sheet material 21 and toner image.In addition, can avoid increasing the size of stepping motor 45, produce the vibrations and the noise of stepping motor 45 in low velocity zone and use vibroshock.
The 4th exemplary embodiment
According to the 4th exemplary embodiment, control paper feeding regularly by the combination of following two kinds of situations.If the speed of imaging device is the maximal rate of a plurality of processing speeds, then the transporting velocity of sheet material 21 is quickened or slowed down, so that sheet material 21 is aimed at toner image.On the other hand,, then present sheet material 21,,, the predetermined point of sheet material 21 in sensor 28 downstreams stopped a period of time along the paper throughput direction then by stopping conveying roller to 27 in timing early if the speed of imaging device is minimum value.Stand-by time depends on that sheet material 21 is sent to the time that sensor 28 is spent from paper feeding.Then, the desirable timing in that sheet material 21 is aimed at toner image restarts by the conveying of conveying roller to 27 pairs of sheet materials 21.
To omit imaging device description by conveying roller is quickened or slows down sheet material 21 is aimed at toner image 27 transporting velocity when the maximum processing speed because superincumbent first with the 3rd exemplary embodiment in carried out relevant description.
Fig. 7 illustrates aiming at of sheet material 21 and toner image, if the speed of imaging device is minimum treat speed, then present sheet material 21 in timing early, be sent to the time that sensor 28 is spent according to sheet material 21 from paper feeding then, by stopping conveying roller to 27, along the paper throughput direction, the predetermined point of sheet material 21 in sensor 28 downstreams stopped a period of time.Then, the desirable timing in that sheet material 21 is aimed at toner image restarts by the conveying of conveying roller to 27 pairs of sheet materials 21.
Thick line among Fig. 7 is the diagram of Y image, and described Y image is formed on the photosensitive drums of the upstream side that places intermediate transfer belt 17.Zone with perpendicular line shade shows the timing morning of presenting the timing ratio expectation of sheet material 21.More particularly, these zones show the position change of sheet material 21 when two supply of sheet material 21 occurring in box 22.On the other hand, the timing evening of presenting the timing ratio expectation that has the zone demonstration sheet material 21 of horizontal line shade.More particularly, these zones show the position change of sheet material 21 when the slip of feed rolls 25 occurring in box 22.
When photosensitive-member 13Y begins imaging,, present sheet material 21 from box 22 in time than the Zao γ of time T g.As mentioned above, time T g is the time that begins to the conveying of sheet material 21 of beginning from imaging.In other words, begun the conveying of sheet material 21 according to arriving described image by the timing of the transfer position of secondary transfer roll 29 transfer printings from box 22 at time sheet material 21 than the Zao γ of toner image.When sensor 28 detected sheet material 21, the conveying of sheet material 21 stopped a period of time.In the desirable timing that sheet material 21 is aimed at toner image, restart the conveying of sheet material 21 according to minimum treat speed Vbmin.Be sent to time that sensor 28 spent according to sheet material 21 from box 22 and determine the length of the stand-by time of sheet material 21.
Then, time γ will be described.Driving feed rolls 25 and conveying roller have following feature to 27 stepping motor 45: if do not restart stepping motor 45 before the vibrations that produce owing to shut-down operation are fully reduced, then stepping motor 45 is easy to imbalance.Therefore, stepping motor 45 needs long relatively stand-by time, is fully reduced up to vibrations.If the length up to the time that vibrations reduce is Tm, sheet material 21 is from maximum two the supply apart from being Ll of box 22, and sheet material 21 is identical with minimum treat speed Vbmin in the transporting velocity of section Ll, and then time γ will be Tm+Ll/Vbmin.Sheet material 21 can be faster than minimum treat speed Vbmin in the transporting velocity of section Ll.
According to this exemplary embodiment, if the speed of imaging device is the maximal rate of a plurality of processing speeds, then presenting sheet material, be moved to deceleration side by the scope of the speed of the control module control of feed rolls 25 and conveying roller being quickened 27 transporting velocity or slowing down in timing early.On the other hand, if the speed of imaging device is the minimum speed of a plurality of processing speeds, then presents sheet material, and, sheet material 21 is stopped a period of time in the precalculated position in sensor 28 downstreams along the paper throughput direction in timing early.Stand-by time depends on that sheet material 21 is sent to the time that sensor 28 is spent from paper feeding.In the desirable timing that sheet material 21 is aimed at toner image, restart the conveying of sheet material 21.Will be described below example in conjunction with above-mentioned situation.
According to this exemplary embodiment, maximum processing speed Vbmax is 200mm/s, and minimum treat speed Vbmin is 50mm/s.When processing speed was maximum processing speed Vbmax, the driving frequency of stepping motor 45 was 1000pps.When processing speed was minimum treat speed Vbmin, the driving frequency of stepping motor 45 was 250pps.Speed control section Lc is 120mm, and it is 100ms that the maximum that is caused by the slip of feed rolls 25 in the box 22 can be accepted paper transportation lag time T s.In addition, if the Zao time α of timing that the paper feeding of sheet material 21 regularly is set to than processing speed when being maximum processing speed Vbmax then is used to adjust maximum and can accepts the transporting velocity of time T s and will be (Vbmax * Lc)/((Lc-Vbmax * (Ts-α)).When processing speed is minimum treat speed Vbmin, transporting velocity will always equal minimum treat speed Vbmin.
Fig. 8 illustrates for sheet material 21 is aimed at toner image, when a plurality of processing speeds comprise feed rolls 25 and conveying roller to 27 acceleration or when slowing down, feed rolls 25, conveying roller are to 27 and drive feed rolls 25 and the conveying roller speed setting range to 27 stepping motor 45.This adjusted value from table, saves deceleration adjusted value, because can not influence feed rolls 25, conveying roller to 27 with drive the speed setting range of the stepping motor 45 of described roller 25 and 27 in maximum processing speed.In addition, because the adjustment of when the processing speed of imaging equipment is minimum treat speed, needn't quickens and slow down, so these adjusted values are not included in the table of Fig. 8.
Table (a) illustrates when α=0ms or under the situation of not using this exemplary embodiment, and feed rolls 25, conveying roller are to 27 and drive feed rolls 25 and the conveying roller speed setting range to 27 stepping motor 45.In this case, feed rolls 25 and conveying roller will be 40-240mm/s to 27 transporting velocity, drive feed rolls 25 and conveying roller and will be 200-1200pps to the driving frequency of 27 stepping motor 45.
Table (b) is illustrated under the situation according to this exemplary embodiment α=50ms, and feed rolls 25, conveying roller are to 27 and drive feed rolls 25 and the conveying roller speed setting range to 27 stepping motor 45.In this case, feed rolls 25 and conveying roller will be 50-218mm/s to 27 transporting velocity, drive feed rolls 25 and conveying roller and will be 250-1091pps to the driving frequency of 27 stepping motor 45.
Table (c) is illustrated under the situation according to the α=100ms of this exemplary embodiment, and feed rolls 25, conveying roller are to 27 and the minimum speed setting range that drives the stepping motor 45 of described roller 25 and 27.In this case, feed rolls 25 and conveying roller will be 50-200mm/s to 27 transporting velocity, drive feed rolls 25 and conveying roller and will be 250-1000pps to the driving frequency of 27 stepping motor 45.
Relation when then, description being printed continuously between the interval of printing efficiency and sheet material 21.Figure 10 illustrates by the conveying with sheet material 21 and stops a period of time and technology that sheet material 21 is aimed at toner image.Figure 11 is illustrated in the technology of under the situation of the conveying that does not need to stop sheet material 21 sheet material 21 being aimed at toner image.The required paper feeding of last technology stops the time of stepping motor 45 at interval to the youthful and the elderly than the latter.
Fig. 9 illustrates the difference of the printing efficiency that whether is stopped according to stepping motor 45.According to this exemplary embodiment, maximum processing speed Vbmax is 200mm/s, and minimum treat speed Vbmin is 50mm/s, and sheet material 21 is 300mm along the size of throughput direction, paper is 100mm at interval, and fully reducing owing to stopping the vibrations time necessary that stepping motor 45 produces is 100ms.Described expressing: when under the situation that does not stop stepping motor 45, when maximum was handled the speed operation imaging device, the time that is used for formation image on sheet material 21 was 1.5 seconds, and paper is 0.5 second at interval, and printing efficiency is 30 pages/second.
On the other hand, under the situation that is stopping stepping motor 45, when maximal rate processing speed operation imaging device, the time that is used for formation image on sheet material 21 is 1.5 seconds, and paper is 0.5 second at interval, and the stand-by time of stepping motor 45 is 0.1 second.In this case, printing efficiency is 28.5 pages/second, thereby greatly reduces printing efficiency.Yet in minimum treat speed, under the situation that does not stop stepping motor 45, printing efficiency is 7.5 pages/second, and under the situation that stops stepping motor 45, printing efficiency is 7.4 pages/second.That is to say that therefore reducing pro rata stand-by time and total processing time of stepping motor 45, with minimum treat speed, stopping and not stopping in the processing of stepping motor 45, printing efficiency only has minimum difference (difference only is 0.1 page/second).
According to this exemplary embodiment, minimize by reduction printing efficiency, even when driving imaging device, also can minimize the scope of the transporting velocity of sheet material 21 with a plurality of processing speeds.Therefore, can do not produce stepping motor 45 owing to the situation that reduces imbalance that torque causes and the size that does not increase stepping motor 45 in high speed range under, realize aiming at of sheet material 21 and toner image.In addition, can avoid producing vibrations and the noise and the use vibroshock of stepping motor 45 in the low velocity zone.
Although described the present invention with reference to exemplary embodiment, it should be understood that: the present invention is not limited to disclosed exemplary embodiment.The scope of claim is consistent with the most wide in range explanation, thereby comprises all modifications, equivalent structure and function.

Claims (10)

1. imaging device, comprising: transfer printing unit is configured to and will be transferred on the sheet material at the image that forms on the image-carrier; And paper feed unit, be configured to present sheet material, described equipment can be provided for forming a plurality of image taking speeds of image on sheet material, the transporting velocity of sheet material is quickened and slowed down, and do not need to stop conveying in the section of sheet material between paper feed unit and transfer printing unit, thereby make sheet material and the image synchronization that forms on image-carrier, described equipment comprises:
Supply unit, the sheet material that is configured to present from paper feed unit is transported to transfer printing unit, and
Control module is configured to control the paper feeding timing from paper feed unit;
Wherein, if form image with first the fastest in the described a plurality of image taking speeds image taking speed or the slowest second image taking speed, then the control module timing of presenting sheet material be different from when presenting sheet material with the image taking speed except first and second image taking speeds paper feeding regularly; And wherein, if image taking speed is first image taking speed, then control module is regularly changed into paper feeding than image taking speed and is different from the regularly Zao timing of paper feeding under the situation of first and second image taking speeds.
2. imaging device as claimed in claim 1, wherein, if image taking speed is second image taking speed, then control module is regularly changed into paper feeding than image taking speed and is different from the regularly Zao timing of paper feeding under the situation of first and second image taking speeds, and when carrying out control and arriving supply unit with convenient sheet material, stop the conveying of sheet material, restart the conveying of sheet material then.
3. imaging device, comprising: transfer printing unit is configured to and will be transferred on the sheet material at the image that forms on the image-carrier; And paper feed unit, be configured to present sheet material, described equipment can be provided for forming a plurality of image taking speeds of image on sheet material, the transporting velocity of sheet material is quickened and slowed down, and do not need to stop conveying in the section of sheet material between paper feed unit and transfer printing unit, thereby make sheet material and the image synchronization that forms on image-carrier, described equipment comprises:
Supply unit, the sheet material that is configured to present from paper feed unit is transported to transfer printing unit, and
Control module is configured to control the paper feeding timing from paper feed unit;
Wherein, if form image with first the fastest in the described a plurality of image taking speeds image taking speed or the slowest second image taking speed, then the control module timing of presenting sheet material be different from when presenting sheet material with the image taking speed except first and second image taking speeds paper feeding regularly; And
Wherein, if image taking speed is second image taking speed, then control module is regularly changed into paper feeding than image taking speed and is different from the regularly late timing of paper feeding under the situation of first and second image taking speeds.
4. as claim 1 or 3 described imaging devices, also comprise:
Image-generating unit is configured to form image on image-carrier;
Wherein, be different from image taking speed under the situation of first and second image taking speeds, paper feeding be set regularly according to the length of the time when beginning to be imaged onto image at image-generating unit and be transported to transfer printing unit.
5. imaging device as claimed in claim 4, wherein, image-generating unit comprises a plurality of photosensitive-members, and image-carrier is the intermediate transfer element that is configured to be carried at the image that forms on a plurality of photosensitive-members.
6. as claim 1 or 3 described imaging devices, also comprise: sensor, be configured to detect sheet material in the section between paper feed unit and transfer printing unit, wherein, control module is sent to the transporting velocity of control sheet material the section of length between sensor and transfer printing unit of the time that sensor spends to quicken or to slow down according to sheet material from paper feed unit.
7. as claim 1 or 3 described imaging devices, wherein, the timing ratio of formation image is from the paper feeding timing morning of paper feed unit on intermediate transfer element.
8. as claim 1 or 3 described imaging devices, wherein, a plurality of image taking speeds are set according to the type of sheet material.
9. imaging device that can be provided on sheet material forming a plurality of image taking speeds of image, described equipment comprises:
Transfer printing unit is configured to and will be transferred on the sheet material at the image that forms on the image-carrier;
Paper feed unit is configured to present sheet material; And
Control module, the transporting velocity that is configured to control sheet material to be quickening and to slow down, and need not stop sheet material in the section between paper feed unit and the transfer printing unit, thereby make the image synchronization that forms on sheet material and the image-carrier,
Wherein, if image taking speed is scheduled to, then control module changes from the paper feeding of paper feed unit regularly according to described image taking speed; And
Wherein, described predetermined speed is the fastest image taking speed or the slowest image taking speed in a plurality of image taking speeds.
10. imaging device as claimed in claim 9 also comprises: sensor, be configured to detect sheet material in the section between paper feed unit and transfer printing unit,
Wherein, control module is controlled the transporting velocity of sheet material to quicken the section between sensor and transfer printing unit or to slow down according to sheet material from the length that paper feed unit is sent to the time that sensor spends.
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