CN101337470B

CN101337470B - Image forming apparatus

Info

Publication number: CN101337470B
Application number: CN2008101283021A
Authority: CN
Inventors: 本山肇
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2007-07-06
Filing date: 2008-07-04
Publication date: 2011-04-13
Anticipated expiration: 2028-07-04
Also published as: KR101041690B1; JP5406472B2; RU2373063C1; CN101337470A; KR20090004756A; JP2009034991A

Abstract

The present invention discloses an image forming device, which is provided with a laser light source having a plurality of laser elements capable of scanning a plurality of lines in parallel in a sub-scanning direction at a second resolution, which is higher than a first resolution of an image to be formed in a main scanning direction, a multiplexer and a laser driver that set a scaling ratio of an image in the sub-scanning direction in response to the first and second resolutions and an image size for image forming, and perform control so as to select and drive any of the plurality of laser elements of the laser light source in response to the scaling ratio that has been set, and an image forming unit that forms an image of lines scanned using laser elements driven by the laser driver on a print medium.

Description

Imaging device

Technical field

The present invention relates to a kind of electrophotographic image forming, wherein,, toner image is transferred to transfer materials (sheet material), and the execution photographic fixing is embodied as picture by using toner to being formed on the image development on the photosensitive-member.

Background technology

Fig. 1 is the diagrammatic sketch of the configuration of traditional color-image forming apparatus.

Described color-image forming apparatus is provided with two boxlike

paper feed units

1 and 2 and manual feed unit 3, and sheet material S is sent into by each from

paper feed unit

1,2,3 optionally.Sheet material S is at the

box

4,5 of

paper feed unit

1,2,3 or coil on 6 and be written into, because the rotation of pick-up roller 7, sheet material S begins to extract out in order from uppermost sheet material.Then, separated by the pair of separated roller by the only uppermost sheet material among the sheet material S of pick-up roller 7 extractions, this a pair of separate roller is made up of feed rolls 8A and delay roller 8B, and described uppermost sheet material is sent to alignment rolls 12, and the rotation of alignment rolls 12 suspends.In this case, be sent to alignment rolls 12 through too much transfer to

transfer roller

9,10 and 11 from having sheet material S that the

paper feeding cassette

4 or 5 of long distance sends into alignment rolls 12.When the front end crash of the sheet material S that is sent to alignment rolls 12 in this manner to the roll gap of alignment rolls 12 and form predeterminedly when annular, the motion of sheet material S is suspended temporarily.The diagonal of proofreading and correct sheet material S by the formation of the described ring condition of advancing.

Downstream from alignment rolls 12, long intermediate transfer belt (endless belt) 13 (it be an intermediate transfer element) with the state arrangement of tension on driven roller 13a, secondary transfer printing opposed roller 13b and idler roller 13c, and the cross-sectional perspective view that is provided with according to triangle basically of formation.In this diagrammatic sketch, intermediate transfer belt 13 rotates according to clockwise direction.On the upper surface of the horizontal cross-section of intermediate transfer belt 13, arrange a plurality of

photosensitive drums

14,15,16 and 17 (forming and carry the color toner image of different colours on it) in order along the direction of rotation of intermediate transfer belt 13.

It should be noted that: along the direction of rotation of intermediate transfer belt 13, the toner image of upstream photosensitive drums 14 articles accompanied redness, next light-sensitive roller 15 carries the toner image of cyan, and photosensitive drums 16 is carried yellow toner image, and photosensitive drums 17 is carried the toner image of black.At first, the exposure of laser LM starts from the photosensitive drums 14 of upstream based on the view data of pinkish red component, to form electrostatic latent image on photosensitive drums 14.As seen this electrostatic latent image becomes by the magenta toner that provides from developer 23.Then, the exposure of laser LC starts from the photosensitive drums 15 based on the view data of cyan component, to form electrostatic latent image on photosensitive drums 15.As seen this electrostatic latent image becomes by the cyan toner that provides from developer 24.Label 22 expression scanner unit, it is the exposure device of photosensitive drums 14 to 17.

Then, beginning to expose photosensitive drums from laser LC after 15 scheduled times in the past, the exposure of laser LY starts from the photosensitive drums 16 based on the view data of yellow color component, to form electrostatic latent image on photosensitive drums 16.As seen this electrostatic latent image becomes by the Yellow toner that provides from developer 25.Then, beginning to be exposed to photosensitive drums from laser LY after 16 scheduled times in the past, the exposure of laser LB starts from the photosensitive drums 17 based on the view data of black component, to form electrostatic latent image on photosensitive drums 17.As seen this electrostatic latent image becomes by the black toner that provides from developer 26.It should be noted that: the

primary charging device

27,28,29 and 30 that is used for equably photosensitive drums 14 to 17 being charged is set at around the photosensitive drums 14 to 17.In addition, arrange

cleaner

31,32,33 and 34, so that after the transfer printing of toner image, remove the toner that sticks on the photosensitive drums 14 to 17.

In the processing that turns clockwise, intermediate transfer belt 13 in turn by

photosensitive drums

14,15,16 and 17 and their corresponding

transfer printing chargers

90,91,92 and 93 between transfer section.For this reason, the toner image of each in magenta, cyan, yellow and the black is transferred to stack intermediate transfer belt 13 each other.

Simultaneously, alignment rolls 12 beginning according to intermediate transfer belt 13 on the position of toner image and the sequential of the front end coupling of sheet material be rotated.For this reason, be sent to alignment rolls 12 and proofreaied and correct the advance sheet material S of condition of its diagonal and be sent to secondary transfer section T2, secondary transfer section T2 is secondary transfer roll 40 on the intermediate transfer belt 13 and the contact portion between the secondary transfer printing opposed roller 13b, and toner image is transferred to sheet material S.

In this manner, the sheet material S through secondary transfer section T2 is sent to fixation unit 35.Then, owing to the roll gap processing partly through being formed by fixing roller 35A in the fixation unit 35 and pressure roll 35B, sheet material S is via fixing roller 35A heating, and via pressure roll 35B pressurization, the toner image of transfer printing is arrived sheet material by photographic fixing.

Through fixation unit 35 and experience the sheet material S that photographic fixing handles and be sent to a pair of distributing roller 37, in addition, be discharged to the outside of equipment, thereby arrive on the discharge dish 38 by a pair of transfer roller 36.

Described imaging device can carry out the imaging of duplexmode.Below, further describe the configuration of imaging device according to the flow process of sheet material S during duplexmode.

When duplexmode is designated, through fixation unit 35 and experience the sheet material S that photographic fixing handles and be sent to reverse path 59 via vertical-path 58.In this case, when baffle plate 60 is opened vertical-path 58, by each to transfer

roller

36,61 and 62 and a pair of reverse rollers 63 transmit sheet material S.

The time point reverse rotation below of described a pair of reverse rollers 63, at described time point, a sheet material S process point P who transmits along the direction of arrow a by a pair of reverse rollers 63, sheet material S transmits the distolateral thereafter front that is in now along the direction of arrow b.Because this operation is above the surface of the sheet material S of transfer printing toner image has become.It should be noted that: a P is provided with baffle plate 64, and this makes sheet material S to advance to reverse path 59 from vertical-path 58, but this makes sheet material S to enter vertical-path 58 from reverse path 59.In addition, test rod 65 is set, has passed through a some P with the rear end of detecting sheet material.

The sheet material S that transmits along the direction of arrow b owing to the reverse rotation of a pair of reverse rollers 63 is sent to once more paper path 67.Then, sheet material S is many to transfer

roller

68 and 11 transfers of a pair of transfer roller by paper path inside once more, and is sent to a pair of alignment rolls 12, to carry out imaging once more.In this manner, sheet material S is sent to secondary transfer section T2 after its diagonal condition of advancing has been registered roller 12 corrections.Then, realize the second imaging example, realized that for described view data the zoom ratio of main scanning direction and sub scanning direction is proofreaied and correct based on the view data that is stored in the video memory (not shown).Then, sheet material S experiences the same treatment with the single face imaging, and is discharged to the outside of equipment.

Then, will the scanner unit 22 that photosensitive drums is exposed be described.

Fig. 2 is the diagrammatic sketch of configuration that is illustrated schematically in a color part of the scanner 22 shown in the conventional example of Fig. 1.

The imaging device of electrofax is provided with exposing unit, and as shown in Figure 2, it shines photosensitive drums 215 (corresponding in

photosensitive drums

14,15,16 and 17 each) with laser, thereby corresponding to the view data of input, forms sub-image on photosensitive drums 215.Exposing unit is provided with lasing light emitter 210, is used to launch diffusion laser.Be converted into parallel laser L1 from lasing light emitter 210 emitted laser via collimation lens 211.Laser L1 is irradiated to polygonal mirror 213, and described polygonal mirror 213 is driven by scanner motor 212 rotations.Then, the laser L1 that has shone on the polygonal mirror 213 is reflected by polygonal mirror 213, and guiding f-θ lens 214.Make the laser that passes through f-θ lens 214 along main scanning direction, photosensitive drums 215 is carried out array sweeping, because the scanning of laser (that is, because scan operation) forms sub-image 216 on photosensitive drums 215 with even velocity.Come the beginning of detection laser scan operation by beam detection sensor (below, be called the BD sensor) 217.Lasing light emitter 210 with photosensitive drums 215 on time that begins to aim at of laser scanning opened by force.In this manner, in the time period that lasing light emitter 210 is opened by force, BD sensor 217 detects the laser of importing by the reflection of polygonal mirror 213, and the output beam detection signal (below, be called the BD signal), this detection signal is the reference signal of the sequential that writes in the imaging of every main scanning line.

Yet in above-mentioned conventional example, the zoom ratio of sub scanning direction is fixed, and therefore, has following problem.For example, these two bigger problems relate to the driving intermediate transfer belt below.

Because such as the problem of the geometry deviation between driven roller 13a and the dummy roll 13c, the speed of intermediate transfer belt 13 changed along with the time.For this reason, with (that is, the sub scanning direction on the sheet material) ideal image position is compared, and forms in succession on intermediate transfer belt 13 in the process of image and produces position difference along the direction of motion of intermediate transfer belt 13.Particularly, form at the four kinds of coloured images that can superpose according to conventional example under the situation of equipment of full-colour image, have following problem: relatively poor color registration and deterioration of image quality occur.Some main cause that these problems occur is as follows:

(1) thickness at intermediate transfer belt is under the situation of h, is expressed as follows by the movement velocity V of intermediate transfer belt that drives with CAV ω and have a driven roller appointment of radius r:

V=(r+h) * ω ... expression formula (1)

Wherein, when eccentricity Δ r is added to driven roller 13a, be expressed as follows by the fluctuation Δ V of the movement velocity V of the intermediate transfer belt 13 of driven roller 13a appointment:

Δ V ω=Δ r ω * ω ... expression formula (2)

Here, ω indicated angle speed (swing circle of driven roller).

Because the velocity perturbation Δ V ω in the swing circle of driven roller 13a, produce displacement in each color image at the swing circle of driven roller 13a.

(2) in addition, also because the fluctuation on the thickness direction that extends on the whole circumference of intermediate transfer belt causes the change by the movement velocity of the intermediate transfer belt of driven roller appointment.As a result, on the sheet material that is transferred as batch processing from middle transfer belt the image of every kind of color from their ideal position displacement, and deterioration of image quality.Also there is following problem: the fluctuation of the picture position that forms on many sheet materials.

Present hypothesis: when driving radius with CAV ω and be the driven roller of r, have thickness fluctuation Δ h, its whole circumference along intermediate transfer belt is extended, and described intermediate transfer belt is around driven roller and have thickness h.In this case, represent fluctuation Δ VL among the movement velocity V of the intermediate transfer belt that drives by driven roller by expression formula (3).

Δ VL=Δ hL * ω ... expression formula (3)

Here, the whole circumference length of L indication intermediate transfer belt.

Fig. 3 and Fig. 4 schematically show the ideal situation that the displacement by fluctuation of the linear velocity of the described band of driven roller appointment and the image that forms thus concerns, and the situation that comprises the problems referred to above.In Fig. 3 and Fig. 4, the phototiming of each exposure device is shown.By the movement velocity of the indication of the time t on trunnion axis intermediate transfer belt, the point-to-point speed v of described band is shown on vertical axis.The parallel demonstration with main scanning direction of the scan line of the every kind of color that forms on intermediate transfer belt, it is shown as write them according to time sequencing such.

Fig. 3 illustrates the ideal situation of intermediate transfer belt with constant speed V motion.Here, following situation is shown: the run duration gap is set corresponding to the installation interval between each the imaging device in the YMCK look on the intermediate transfer belt, described intermediate transfer belt is with constant speed movement, and along sub scanning direction, the time is provided with each part that writes along main scanning direction at regular intervals.As a result, clearly, under situation about not departing from, have the interval of rule and write in the YMCK chromoscan line each along sub scanning direction.

Relative therewith, Fig. 4 illustrates such a case, and wherein, the speed of intermediate transfer belt changes owing to the thickness of intermediate transfer belt and the eccentricity of driven roller.The little AC component fluctuation of the velocity perturbation of the intermediate transfer belt of being represented by solid line is corresponding to the centrifugal circulation of driven roller, and the big wavy component that is illustrated by the broken lines relates to the corresponding velocity perturbation of circulation in uneven thickness with intermediate transfer belt.

In this case, though when the scan line of every kind of color all when sub scanning direction has rule and forms at interval, in the subscan at interval of scan line, exist with intermediate transfer belt in the corresponding misalignment of speed wave momentum.In addition, as the result who occurs this situation respectively for every kind of color, in the YMCK color, produce relatively poor color superimposition.

2004-102039 number open Japan Patent of special permission proposes a kind of method that this problem is remedied of being used for, and wherein, the rotary speed of control polygonal mirror scanner motor is proofreaied and correct to realize the sub scanning direction zoom ratio.Yet the response speed of the speed of rotation of motor is restricted.For this reason, although this method produces effect for zoom ratio over a long time is inhomogeneous, the uneven displacement effect of its zoom ratio for short-term is relatively poor.

In addition, also there is following problem: during duplex printing, have vertical departing from the image.As everyone knows, common sheet material (such as paper) is owing to cause in the sheet material contained humidity amount to change and expansion or shrink (degree be 2% or still less) slightly in the photographic fixing heating.In other words, the front of sheet material form and the photographic fixing image after, the expansion or the contraction of image appear along with the expansion of sheet material or contraction.After this, when recovering just often as yet, when the reverse side of sheet material is embodied as picture, on the sheet material of expansion or contraction, form and the photographic fixing image in expansion/contraction.After the special time after this, when the image zoom ratio of recovery of the water yield in the sheet material and direct picture is recovered its original size, image on the reverse side undesirably oppositely shrinks or expansion, produces slight inconsistent in this zoom ratio between front and reverse side.

Along with picture quality is more and more higher in recent years, occur proofreading and correct the slight inconsistent needs in this zoom ratio.As mentioned above, proposed to be used for method that this problem is remedied, its rotary speed by control polygonal mirror scanner motor realizes that the auxiliary direction zoom ratio proofreaies and correct.Yet this makes and is necessary to change the rotary speed of motor between sheet material, thereby must be kept for changing the unnecessary time of speed between sheet material.This plays minus effect for printing effect.

Summary of the invention

Above-mentioned traditional problem is eliminated in expectation.

One embodiment of the application's invention uses the laser component of a plurality of multi-strip scanning lines that can scan simultaneously and expose, and optionally drive these laser components, change the sub scanning direction resolution ratio of the image that will form thus, and make it possible to adjust size on the sub scanning direction of image.

According to an aspect of the present invention, provide a kind of and be used to use electrophotographic method to come the imaging device of imaging, it comprises:

Scanning element has a plurality of laser components, and described a plurality of laser components can scan many lines along sub scanning direction abreast with second resolution ratio, and described second resolution ratio is higher than first resolution ratio of the image that will form along main scanning direction.

The zoom ratio setting device is used in response to first and second resolution ratio and the image size that is used for imaging the zoom ratio of image along sub scanning direction being set,

Driving control device is used for carrying out control in response to the zoom ratio that is provided with by the zoom ratio setting device, thus any laser component in a plurality of laser components of selection and driven sweep unit, and

Imaging device is used for forming on print media by the image of scanning element use by the line of the laser component scanning of drive control device drives.

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

Imaging device, have a plurality of scan lines and produce part, each is used for according to making light beam along scan line and scanned image bearing member to its view data that applies, the scan line that described a plurality of scan line produces part is parallel to each other, and the preset space length that is spaced apart from each other, described preset space length is less than the distance between centers of tracks of view data; And

The distance between centers of tracks adjusting device, be connected with the spacing that receives view data and be used to adjust the spacing of scan line and adjust data, it is used for control view data is applied to described a plurality of scan line generation part, thereby the view data of two continuous lines of view data is applied to scan line and produces part, and each bar scan line that described scan line produces part is spaced apart the interval different with the view data distance between centers of tracks.

With reference to the description of accompanying drawing to exemplary embodiment, other characteristics of the present invention and aspect will become clear by following.

Description of drawings

The accompanying drawing that is merged in specification and constitutes the part of specification illustrates embodiments of the invention, and is used to explain principle of the present invention together with the description.

Fig. 1 is the diagrammatic sketch that the configuration of traditional color-image forming apparatus is shown.

Fig. 2 is the diagrammatic sketch that schematically shows the color configuration partly of scanner shown in Figure 1.

Fig. 3 be illustrate picture position displacement relation diagrammatic sketch and ideal situation is shown.

Fig. 4 is the diagrammatic sketch that schematically shows the relation of picture position displacement.

Fig. 5 is the diagrammatic sketch that is used to describe according to the critical piece of the imaging moiety of the electrophotographic printer of the semiconductor laser of the use multiple beam type of exemplary embodiment.

Fig. 6 illustrates according to the semiconductor laser of the multiple beam type of present embodiment and the diagrammatic sketch of drive circuit thereof.

Fig. 7 is the diagrammatic sketch that carries out imaging along sub scanning direction when using 8 laser instrument LD1 to LD8 that is used to describe according to first embodiment.

Fig. 8 is used to be described in realize expanding the operation under the line situation is at interval widened in correction from state shown in Figure 7 diagrammatic sketch.

Fig. 9 is used to describe the diagrammatic sketch of realizing shrinking the operation under the situation of proofreading and correct according to first embodiment of the invention.

Figure 10 A is the diagrammatic sketch that is used to describe the switching that the laser instrument of each scanning shown in Figure 8 drives to Figure 10 C.

Figure 11 A is the diagrammatic sketch that is used to describe the switching that the laser instrument of each scanning shown in Figure 9 drives to Figure 11 C.

Figure 12 is the diagrammatic sketch that carries out imaging along sub scanning direction when using 8 laser instrument LD1 to LD8 that is used to describe according to second embodiment.

Figure 13 is the diagrammatic sketch that is used to describe the example of second embodiment, wherein, carry out and proofread and correct, thereby image is expanded along sub scanning direction with respect to Figure 12.

Figure 14 is the diagrammatic sketch that is used to describe the example of second embodiment, wherein, realizes shrinking from state shown in Figure 12 and proofreaies and correct.

Figure 15 is the block diagram that illustrates according to the configuration of the controller of the color-image forming apparatus of present embodiment.

Figure 16 is the flow chart that is used to describe the processing that the controller by color-image forming apparatus according to present embodiment carries out.

The specific embodiment

Below, describe each embodiment of the present invention with reference to the accompanying drawings in detail.The claim be not meant to limit the present invention is below described, and, be not that all combinations of the feature described in an embodiment all are necessary for solution of the present invention.

In recent years, in order in printer and duplicator, to realize higher speed and the picture quality of Geng Gao, many technology have been realized, wherein, use polygonal rotating mirror to increase doubly and the exposure of many lines of realization in single scanning as the number of beams of the semiconductor laser (laser component) of lasing light emitter.Particularly, shift from edge emitted laser device, surface emitting laser has dropped into practical application, simplifies the realization of multiple beam thus.

Below, a kind of example will be described, wherein, in imaging device, use the semiconductor laser of multiple beam type.It should be noted that: about the configuration according to the imaging device of this embodiment, use the semiconductor laser of multiple beam types except scanner unit 22, described configuration is common for the above-mentioned configuration of imaging device shown in Figure 1.Also note that: Fig. 1 illustrates the example of using intermediate transfer belt, but also has the method for directly carrying out transfer printing from photosensitive-member at sheet material.

Fig. 5 is the diagrammatic sketch that is used to describe according to the critical piece of the imaging moiety of the electrophotographic printer of the semiconductor laser of the use multiple beam type of present embodiment.

In Fig. 5, label 1015 indication polygonal rotating mirrors, label 1016 indications drive the laser scans device motor of polygonal mirror 1015 rotatably.Label 1017 indication laser diodes, it is the light source that is used to expose.Laser diode 1017 is driven by laser driver 1029, thereby opens or close in response to picture signal.Shone to polygonal rotating mirror 1015 from the light modulation laser of laser diode 1017 emissions.

Be accompanied by the rotation of polygonal rotating mirror 1015, reflected by its plane of reflection respectively from laser diode 1017 emitted laser, as each deflected beam with the angle of continuously changing.Reverberation experiences the correction that is used for distorton aberration etc. by the lens group (not shown), advance via transmitter 1018 then, with the main scanning direction (with respect to the vertical direction of diagrammatic sketch) of scanning photosensitive drums 1010.The one side of polygonal rotating mirror 1015 is corresponding to single pass.Correspondingly, launching from laser diode 1017 under the situation of 8 light beams, 8 laser rays scan the main scanning direction of photosensitive drums 1010 abreast by the once rotation of polygonal rotating mirror 1015.

Charged by charger 1011 in advance in the surface of photosensitive drums 1010, and one after the other the scanning by laser exposes, to form the electrostatic latent image of many lines.In addition, photosensitive drums 1010 is according to the direction rotation of arrow, thereby the electrostatic latent image that has formed by laser develops by the toner that provides from developer 1012.The visual image of Xian Yinging is transferred to by transfer printing charger 1013 and is with 1014 as intermediate transfer element in this manner.In this manner, the transfer printing by visual image produces described with on toner image be transferred and photographic fixing to the sheet material of secondary transfer section, after this, described sheet material is discharged to device external.

Here, at the lateral parts of photosensitive drums 1010, BD sensor 1019 along main scanning direction be arranged near or corresponding to scanning the starting position the position.Every laser by each plane of reflection reflection of polygonal rotating mirror 1015 was detected by BD sensor 1019 before its scanning.Detected in this manner BD signal is transfused to controller 1027, begins reference signal as the scanning of main scanning direction.Controller 1027 by with the signal of BD sensor 1019 with for referencial use, produce and control and write the clock signal starting position synchronised, FIFO 1028 and laser driver 1029 along the data of the main scanning direction of every line.

Memory 1031 storage indications are along the data of the big or small undulate quantity of sub scanning direction, and it is for the image varying cyclically that is formed by imaging device (imaging mechanism that comprises above-mentioned photosensitive drums 1010 and transfer belt 1014).In this manner, controller 1027 is controlled and will be adjusted the resolution ratio along sub scanning direction thus by the switching of the described line of multiplexer 1030 (being described to Figure 11 C with reference to Figure 10 A after a while) realization according to the data of storage.

And, in addition, the detector (not shown) can be set, it detects along the big or small undulate quantity of the sub scanning direction of the image that is formed by imaging device, and this undulate quantity changes circularly.In this manner, controller 1027 is controlled the switching of the described line that will be realized by multiplexer 1030 according to the undulate quantity that detects, thereby adjusts the resolution ratio along sub scanning direction.It should be noted that, described detector can comprise following function, described function is used for, detect during the duplex printing when print when positive sheet material (print media) size and when the gap (expansion/contraction ratio) between the sheet material size during at the back side of described sheet material formation image after photographic fixing.This allows during duplex printing, and the correcting image size is in the front of sheet material and the difference between the reverse side.

In this manner,, produce the light pulse signal that is used for semiconductor laser, photosensitive-member is realized image exposure, to carry out imaging based on electronic image signal by using semiconductor laser device driving circuit.

Fig. 6 illustrates according to the semiconductor laser of the multiple beam type of present embodiment and the diagrammatic sketch of drive circuit (corresponding to the laser driver 1029 of Fig. 5) thereof.

Laser diode 1017 among Fig. 5 is corresponding to the semiconductor laser 100 of Fig. 6.In semiconductor laser 100, encapsulating 8 laser instrument LD1 of internal placement to LD8.Laser instrument LD1 to the cathode terminal of LD8 via public terminal ground connection.In addition, laser instrument LD1 to the anode terminal of LD8 be connected respectively to drive circuit 101,102,103,104 ..., 108, and provided photoelectric current by the corresponding driving circuit.Drive circuit is respectively the circuit that is equal to, here by with drive circuit 101 as representing example to provide description for the operation of described circuit.

For each the light quantity of monitoring laser device LD1, photodiode 110 is arranged in light or its a part of irradiated position of laser instrument LD1 to the LD8 emission to LD8.The anode terminal of photodiode 110 is grounded, and its cathode terminal is connected to power source voltage Vcc via resistance R 1.Cathode terminal is the output that is used to monitor.The cathode terminal of photodiode 110 is connected to op-amp's 111 (OP1)+input (non-return) terminal.In addition, reference voltage Vref is applied to op-amp 111-input terminal.

The lead-out terminal of op-amp 111 is imported into analog switch SW1.The control signal that signal cont1 provides for slave controller 1027, it is transfused to the control terminal of the operation of control analog switch SW1.The output of analog switch SW1 is connected to an end of capacitor C 1, in addition, is transfused to the control signal as constant-current source CC1.The other end of capacitor C 1 is grounded.Constant-current source CC1 is output current in response to the voltage that provides via analog switch SW1 (control voltage).The emitter terminal of PNP transistor Q10 and Q11 is connected respectively to the output of constant-current source CC1.The collector terminal of PNP transistor Q10 is the output of drive circuit 101, and is connected to the anode terminal of laser instrument LD1.Resistance R D1 is connected to the collector terminal of PNP transistor Q11, and the other end of resistance R D1 is grounded.Signal data1 (view data) is imported into the base terminal of PNP transistor Q10 via reverser Q12.In addition, signal data1 is input to the base terminal of PNP transistor Q11 via buffer Q13.Provide signal data1 from FIFO shown in Figure 5 1028.The configuration of other drive circuit also is identical.Then, with the description that provides about the operation of sort circuit.

At first, controller 1027 outputs all at the signal cont1 and the signal data1 of high level, are controlled (APC) pattern so that begin the automated power of laser instrument LD1.At this moment, at low-level output signal cont2 to cont8 and signal data2 to data8.

Because signal data1 is high level at this moment, so the output of reverser Q12 is low level, and PNP transistor Q10 conducting.In addition, PNP transistor Q11 oppositely turn-offs.As PNP transistor Q10 by this way during conducting, laser instrument LD1 is because the electric current that constant-current source CC1 provides and luminous.Then, when when laser instrument LD1 emitted laser amount increases, the electric current that flows to photodiode 110 increases, and the voltage that is input to op-amp 111 descends.Op-amp111 compares the voltage and the reference voltage Vref of photodiode 110, the line operate of going forward side by side, thus the output voltage of op-amp 111 descends when the voltage of photodiode 110 descends.When the output voltage of op-amp 111 descended by this way, the control voltage of constant-current source CC1 descended, thereby its output current also descends.When the output current of constant-current source CC1 descended by this way, the drive current of laser instrument LD1 also descended, and also descended from laser instrument LD1 emitted laser amount.

Drive circuit 101 uses negative-feedback circuit to realize APC in the above described manner, and the luminous of laser instrument LD1 is driven, thereby the output of photodiode 110 equates with reference voltage Vref.It also is identical being controlled to the driving of LD8 by 102 to 104 and 108 couples of laser instrument LD2 of other drive circuit.

Then, will be described about the operation during printing.

Under printing model, 1027 signal cont1 are set to low level to signal cont8 by controller, export the view data that is used for imaging at signal data1 in data8.

Because signal cont1 is a low level at this, so analog switch SW1 closes.For this reason, keep voltage during the APC pattern by capacitor C 1.Because the voltage of capacitor C 1 charging is applied to the control terminal of constant-current source CC1, thus the output of constant-current source CC1 become with the APC pattern during identical current value.

When signal data1 is high level, PNP transistor Q10 conducting, therefore, laser instrument LD1 is luminous.On the contrary, when signal data1 was low level, PNP transistor Q10 turn-offed, and therefore, laser instrument LD1 closes.In this manner, can use view data (data1) to realize driving, and can realize exposure and scanning in response to described view data for opening and closing laser instrument LD1.In addition, be well known that: the laser of semiconductor laser emission constant basis, as long as their driving current value is identical under same environment.In this manner, between light emission period, laser instrument can be driven to having the constant light quantity that is equal to the APC pattern.

In addition, when signal data1 was high level, PNP transistor Q11 turn-offed, when signal data1 is low level, and PNP transistor Q11 conducting.Therefore, when signal data1 was low level, the electric current that provides from constant-current source CC1 was applied to resistance R D1.In this manner, always provide electric current by constant-current source CC1, and be not subjected to the condition influence of signal data1, its current value becomes steady state value.Usually,, particularly carry out handover operation to be embodied as when picture, can have difficulty with tens of MHz when utilizing constant-current source to carry out high-speed driving.Yet, utilize this configuration, although PNP transistor Q10 and Q11 need handover operation at a high speed, constant-current source CC1 does not need the high speed handover operation, therefore, imaging is relatively easy.The situation of utilizing other laser instrument LD 2 to LD 8 to print also is same.

Then, with reference to Fig. 7, use description to when using the multi-beam laser device, adjust the laser-driving method of the sub scanning direction resolution ratio of the image that will form.

Fig. 7 is used to describe the diagrammatic sketch that carries out imaging according to sub scanning direction when using 8 laser instrument LD 1 to LD 8.Here, will describe following situation: the resolution ratio of each bar line of the sub scanning direction (vertical line among Fig. 7) that will be formed by these laser instruments is four times of resolution ratio of main scanning direction (horizontal direction among Fig. 7).

In Fig. 7, be designated the line that the line indication of LN 1 to LN 8 can be scanned by 8 laser instrument LD 1 to LD 8 in a laser scans.Here, the resolution ratio (second resolution ratio) of line LN 1 to LN 8 is set to four times of resolution ratio (first resolution ratio) of view data.That is to say, be under the situation of 600dpi in the resolution ratio of view data, and the resolution ratio of laser diode 1017 (sub scanning direction resolution ratio) becomes 2,400dpi.In Fig. 7, the exposed lines of the luminous driving of laser instrument, the non-luminous line of dotted line indication laser are enabled in the solid line indication.Here, when resolution ratio is 2, during 400dpi, the interval of every scan line (preset space length) is approximately 10.6 μ m.

In the example of Fig. 7, the exposed lines of enabling the luminous driving of laser instrument in first scanning is line LN1 and LN5 by the solid line indication.Exposed lines LN 1 and LN 5 are corresponding to laser instrument LD 1 and LD 5.In this manner, by utilizing laser instrument to expose for per 4 lines along sub scanning direction, sub scanning direction resolution ratio becomes 2,400/4, promptly, resolution ratio is 600dpi, and the resolution ratio (distance between centers of tracks) of itself and view data is complementary, and the interval of the exposed lines that forms along sub scanning direction becomes near 42.3 μ m.

Then, have analogue for second scanning, the exposed lines of enabling the luminous driving of laser instrument is the line LN 1 and the LN 5 of solid line indication.Then, for third and fourth scanning, there is analogue, the exposed lines of the luminous driving of enabling laser instrument is set.

Utilize the image that exposes at interval and scan in the manner described above and expose along the always uniform line of sub scanning direction in first scanning, second scanning etc.In imaging subsequently, not influence in uneven thickness in band driving in the transfer paper and the expansion/contraction etc., and there is no need under the situation of the image size in the corrected sub scanning direction, can be by driving laser instrument as shown in Figure 7, obtain the image that has equal resolution at main scanning direction and sub scanning direction.

Yet, because the band in the transfer paper (sheet material) drives and expansion/contraction etc. in influence in uneven thickness cause under the situation different with the expectation resolution ratio of view data, be necessary to carry out and control, thus corrected sub scanning direction intervals.Operation under the situation that realizes described correction control is described with reference to Fig. 8 and Fig. 9.

Fig. 8 is used to be described in realize expanding the diagrammatic sketch of proofreading and correct with the operation under the situation of widening the exposed lines of opening with state interval shown in Figure 7.In Fig. 8, line in per four lines that make as shown in Figure 7 and main scanning direction resolution ratio were complementary commonly, establishment four line gaps between the exposed lines of first scanning and second scanning were to expand image along sub scanning direction.In other words, the view data of two consecutive lines is applied to the laser component that scan line spacings is opened 4 lines commonly.This is corresponding to first scan cycle.Mode can be applied to the view data of two consecutive lines the laser component that scan line spacings is opened 5 lines as an alternative.This is corresponding to second scan cycle.Here, scan cycle is 4 or 5 scan lines, and corresponding to a line of view data, and 8 lines of " first scanning " among Fig. 8, " second scanning ", " the 3rd scanning " etc. are corresponding to 8 laser components (scan line generation part).In Fig. 8, the exposed lines of the luminous driving of laser instrument is enabled in the solid line indication equally, and the dotted line indication does not have the line of drive laser.In first scan cycle, as shown in Figure 7, when resolution ratio is 2, during 400dpi, the about 10.6 μ m of the intervals of scan line.

During second time line sweep, the laser instrument of enabling luminous driving is LD 2 and LD 6, and exposed lines is line LN 2 and the LN 6 by the solid line indication.Then, in the 3rd scanning, exposed lines is line LN 2 and the LN 6 (and these are corresponding to laser instrument LD 2 and LD 6) that is indicated by solid line as in second scanning.The 4th time exposed lines is in this manner similarly by successive scanning.

Start from the LN 5 in first scanning and end at 5 lines of LN 1 in second scanning corresponding to the second above-mentioned scan cycle.Article 5, have only 1 line (that is, line LN 5) to be activated in the line, and second line of view data is applied to line LN 5.The image that scans by this way and expose has between first scanning and second scanning along the exposed lines of sub scanning direction interval (interval between the three-way LN 2 of the second-line LN 5 of application image data and application image data), this exposed lines is at interval near 52.9 μ m (it approximates the interval of 42.3 μ m+ corresponding to 1 scan line greatly), and described image is compared with the situation of Fig. 7 and become longer.That is to say, compare that there is about 25% expansion in the interval between the second and three-way scan line that is used for view data with situation shown in Figure 7.Yet, scan before this and afterwards exposed lines with interval as shown in Figure 7 near 42.3 μ m (600dpi).Therefore, for image as a whole, determine the sub scanning direction zoom ratio in first scan cycle by the frequency that second scan cycle is provided.

In other words, when passing through in every n scan cycle, (for example to use one time second scan cycle, (n-1) the individual first scan cycle heel has one second scan cycle) when carrying out expansion, and when first scan cycle had 4 lines and second scan cycle and has 5 lines, the expansion zoom ratio that is used for image as a whole can be expressed as follows:

25÷n(％)

For example, by with per 25 lines (per 25 scan cycle) frequency once of view data according to expanding image along sub scanning direction corresponding to the interval of 1 line, and 4 line exposing lines that carry out " normally " along sub scanning direction for remaining 24 image line datas at interval, can expose along the image of sub scanning direction expansion 1%.Select driven exposed lines (laser component) in response to the zoom ratio (zoom ratio setting) that is provided with by this way.

Be described in the luminous method of LD of controlling at this moment with reference to Figure 10 A to Figure 10 C.

Figure 10 A is the diagrammatic sketch that is used to describe the switching that the laser instrument of each scanning shown in Figure 8 drives to Figure 10 C.Should note: use same label to show the part shared with Fig. 5.

Figure 10 A illustrates the block diagram that the view data among the FIFO 1028 is offered the path of laser driver 1029.

The data of 2 lines are input to multiplexer 1030 from FIFO 1028, described 2 lines be the preceding line (Fig. 8 first scanning in line LN 1) and after line (Fig. 8 first scanning in line LN 5).Multiplexer 1030, is selected among the LD 1 to LD 8 driven one or more laser instruments with the line data that output is imported thus according to coming the control signal of self-controller 1027 to select laser driver.In this manner, the laser instrument of being selected by multiplexer 1030 is activated, and laser response stands luminous driving in view data.

Figure 10 B is illustrated in first scan period of Fig. 8, the hand-off process of being undertaken by multiplexer 1030.Here, will be the preceding line offer laser instrument LD 1, will after line offer laser instrument LD 5.

Figure 10 C is illustrated in second to the 4th scan period of Fig. 8, the hand-off process of being undertaken by multiplexer 1030.Here, will be the preceding line offer laser instrument LD 2, will after line offer laser instrument LD 6.

Then, with the operation of describing under the situation that has realized shrinking correction among Fig. 9.

In Fig. 9, will be in scanning for the first time in 1 to LN 8 indication of the line LN shown in the scanning for the first time by the exposed lines of laser instrument LD 1 to LD 8 scanning.In addition, here, according to identical before mode, the resolution ratio of laser diode 1017 be set to four times of the resolution ratio of image (600dpi) (2,400dpi).The scan line of solid line and dotted line indication laser diode 1017, the exposed lines of luminous driving is enabled in the solid line indication.In addition, here, the interval of scan line is corresponding to 2, the resolution ratio of 400dpi, and therefore, by 1 line of exposure in 4 lines, the main scanning direction resolution ratio of itself and 600dpi is complementary.Therefore, in scanning for the first time, the luminous driving of enabling laser instrument for line LN 1 and LN 5 (corresponding to laser instrument LD 1 and LD 5) by the solid line indication.

Then, during second time line sweep, line LN 1 and LN 5 are identical with scan period for the first time, just two lines at interval (line LN 6 and LN 7) add line LN8 afterwards in addition.Then, in scanning with the 4th time for the third time, line LN 4 and LN 8 are set to exposed lines, for described exposed lines, according to realizing at interval that with 3 identical before lines laser instrument is luminous.

In this manner under the scanning and the situation of exposure image, in scanning for the second time, the interval between exposed lines LN 5 and the exposed lines LN 8 is near 31.7 μ m (it equals the interval that 42.3 μ m (600dpi) deduct 10.6 μ m).In this manner, realize and the proportional minimizing of single sweep line, that is, and 25%.This is corresponding to line second scan cycle at interval of " minimizing " with 3 lines.Here, scan before this and afterwards exposed lines with intervals near 42.3 μ m (600dpi), it is corresponding to first scan cycle (the line interval that all has " normally " of 3 lines), therefore, be identified for the sub scanning direction zoom ratio of image as a whole by the frequency that second scan cycle is provided in first scan cycle.

In other words, when passing through in every n scan cycle, (for example to use one time second scan cycle, (n-1) the individual first scan cycle heel has one second scan cycle) when carrying out shrinkage operation, and when first scan cycle had 4 lines and second scan cycle and has 3 lines, the contraction zoom ratio that is used for image as a whole can be expressed as follows:

25÷n(％)

For example, reduce scan line spacings, and carry out scanning and exposure according to the subscan intervals of " normally ", can form and reduce 1% image for remaining 24 image line datas by per 25 lines frequency once with view data.Select driven exposed lines (laser component) in response to the zoom ratio (zoom ratio setting) that is provided with by this way.

Figure 11 A is to be used to describe the diagrammatic sketch of the driving control of laser instrument LD at this moment to Figure 11 C.

In Figure 11 C, will be provided to multiplexer 1030 from FIFO 1028 at Figure 11 A as 3 three-way line data of first line to the.Multiplexer 1030 offers the line data of input according to the control signal of coming self-controller 1027 laser driver of corresponding laser instrument LD 1 to LD 8.In this manner, have only the laser instrument experience of importing data luminous, and enable exposure corresponding to the exposed lines of described laser instrument.

Figure 11 A illustrates the scan condition first time among Fig. 9.Here, first-line data are provided for laser instrument LD 1, and second-line data are provided for laser instrument LD 5.Carry out control, thereby three-way data can not be provided for laser driver 1029.

Figure 11 B is illustrated in the scan condition second time among Fig. 9.First-line data are provided for laser instrument LD 1, and second-line data are provided for laser instrument LD 5, the three-way data and are provided for laser instrument LD 8.

Figure 11 C is illustrated in third and fourth scan condition among Fig. 9.In this case, first-line data are provided for laser instrument LD 4, and second-line data are provided for laser instrument LD 8.Carry out control, thereby three-way data are not provided for laser driver 1029.

Form image by adjusting sub scanning direction resolution ratio in this manner, drive the image that produces of circulate along the contraction of sub scanning direction or expand and to be corrected according to band.

In addition, can proofread and correct contraction or the expansion of image that the expansion/contraction owing to sheet material produces in a comparable manner along sub scanning direction.Consider following situation, that is, in duplex printing, be applied to during owing to the image in the front that is formed on sheet material in photographic fixing the heat of described sheet material and pressure make the size of sheet material shrink or expansion after, image will be formed on the back side of described sheet material.If contraction of known sheet material size at this moment or expansion ratio, then can carry out adjustment, thereby pass through according to arriving the mode that Figure 11 describes with reference to Fig. 8 before, according to described ratio the size of the image that will form at the back side of sheet material is expanded or shunk, become equal in the size of the image of the front and back formation of sheet material.

Second embodiment

Then, with reference to the imaging operation of Figure 12 description according to second embodiment of the invention.

In Figure 12, can be in scanning for the first time in 1 to LN 8 indication of the line LN shown in the scanning for the first time by the exposed lines of laser instrument LD 1 to LD 8 scanning.Here, the sub scanning direction resolution ratio of laser diode 1017 is set to 1.2 times of resolution ratio of view data.For example, be 1 in the resolution ratio (distance between centers of tracks) of view data, under the situation of 200dpi, the sub scanning direction resolution ratio of laser diode 1017 becomes 1,440dpi (near the scan line spacings of 17.6 μ m-or preset space length).In Figure 12, the exposed lines of the luminous driving of laser instrument is enabled in the solid line indication.

In scanning for the first time, line LN 1 realizes the luminous exposed lines of laser instrument to LN 5, LN 7 and LN 8 indications.That is to say, by rarefaction that 1 line in 6 scan lines is become, 1, the sub scanning direction resolution ratio of 440dpi can match 1 substantially, the horizontal direction resolution ratio of 200dpi.

In other words, by 5 lines in 6 scan lines that expose, average headway is spaced apart:

17.6×6÷5＝21.1

This equals substantially near 21.2 μ m, and it is for being 1 when resolution ratio, and the exposed lines during 200dpi at interval.

By scanning in the second time subsequently in the 4th scanning, 5 lines in 6 scan lines that expose in a similar fashion can be corresponding to forming image near 21.2 μ m on sub scanning direction, and also for being 1 when resolution ratio, the exposed lines during 200dpi at interval for it.

Then, the image that uses Figure 13 and Figure 14 to describe when realizing that described correction is controlled is expanded and is shunk.

Figure 13 is the diagrammatic sketch that is used for describing with reference to Figure 12 following example, wherein, carries out and proofreaies and correct, thereby expand image along sub scanning direction.

In Figure 13, will be in the scanning first time of laser diode 1017 in 1 to LN 8 indication of the line LN shown in the scanning for the first time by the exposed lines of laser instrument LD 1 to LD 8 scanning.In this case, the resolution ratio of laser diode 1017 is set to 1.2 times of resolution ratio of view data.In scanning for the first time, select exposed lines according to the mode identical, with coupling sub scanning direction resolution ratio and horizontal direction resolution ratio with Figure 12.Line LN 1 to LN 6 is corresponding to first scan cycle of enabling 5 lines in 6 lines.In this case, 5 lines that begin most of view data are applied to the laser component that LN 1 arrives LN 5 respectively.

Then, during second time line sweep, enable line LN 1, LN 2 and LN 4 to LN8.In this manner, begin to continue from the scan line LN 1 to LN 6 of last circulation, the line of next circulation is the line LN 7 of scanning for the first time and the line LN 1 to LN3 of scanning for the second time.The line LN 1 and the LN 2 of the line LN 7 of scanning and LN 8 and scanning for the second time are the exposed lines of enabling exposure for the first time.Therefore, in this scan cycle as second scan cycle, next 4 lines (LN 7, LN8, LN 1 and LN 2) in 5 scan lines (LN 7, LN 8, LN 1 to LN 3) are exposed.The 6th line to the 9 lines of view data are applied to the laser component of LN7, LN 8, LN 1 and LN 2 respectively.Therefore, the 10th line of view data that is applied in Figure 12 the laser component of line LN 3 in the scanning for the second time is applied to the laser component that is used for line LN 4 second time in the scanning among Figure 13 now, and this makes image expand the amount of certain ratio along sub scanning direction.In addition, in scanning for the second time, line LN 4 to LN 8 is the exposed lines of enabling exposure, and it constitutes another scan cycle, and wherein, 5 lines in 6 lines of the line LN 1 that ends to scan for the third time are exposed.Similarly, the line LN 2 that another circulation starts from scanning for the third time, the line LN 7 that ends to scan for the third time.Described circulation is another first scan cycle, wherein, enables 5 exposed lines in 6 lines to expose.During second scan cycle, 4 lines in 5 lines of scanning are exposed for the first time, and therefore, the intervals of on average exposing is:

17.6×5÷4＝22.0

This expression is compared with first scan cycle, has expanded 4.2% along sub scanning direction.Here, corresponding to first scan cycle, form before this and afterwards exposed lines according to intervals, therefore, determine that by the frequency that second scan cycle is provided image is in this case along the zoom ratio of sub scanning direction in first scan cycle near 21.1 μ m.

That is to say that when being in the line of m in quantity, when realizing dilation procedure corresponding to the interval of one time one line, the total quantity of scan line becomes 6 ÷, 5 * (m-4)+5 lines.In this expression formula, the processing that " 6 " indication is a unit with 6 lines will be used 5 lines in described 6 lines of " 5 " indication, and " m " indication will be inserted 1 line in every m line of view data, to use 4 lines in 5 lines of " 4 " indication, 5 lines that " 5 bar line " indication is used to expand are handled.

Since the total quantity of scan line under the situation that does not realize described correct operation for (6 ÷, 5 * m) lines, so the sub scanning direction zoom ratio is represented by following expression:

((6÷5×(m-4)+5)-(6÷5×m))÷(6÷5×m)×100[％]＝100÷6÷m[％]

For example, realize in expectation under the situation of 1% expansion, can realize proofreading and correct by inserting exposed lines according to 16.67 lines ratio once.Although the actual quantity of line is necessary for natural number, can use described ratio to come the number of times of calculation correction operation, for example, proofread and correct by the expansion that in 1,667 scan line, realizes 100 1 exposed lines, can obtain the image of expansion 1% on the sub scanning direction.

Then, Figure 14 is used to describe the diagrammatic sketch of realizing the operation under the situation of shrinkage operation from the state shown in Figure 12.

In Figure 14, scanning is identical with the situation of Figure 12 for the first time.

Next, in scanning for the second time, the exposed lines of enabling exposure is line LN 1 to LN 4 and line LN 6 to LN 8.In this manner, the line LN 1 to LN 4 of the line LN 7 to LN 8 of scanning and scanning for the second time is the exposed lines of enabling exposure for the first time.That is to say that 6 exposed lines that end in 7 continuous sweep lines of the line LN 5 of scanning for the second time are activated to expose.In this manner, the line of view data that is applied to the laser component of the line LN 5 in the second time scanning among Figure 12 is applied to the laser component of the line LN 4 in the scanning second time among Figure 14, and it makes image shrink a certain proportion of amount along sub scanning direction.

Then, 5 lines that start from line LN 6 that scans for the second time and the line LN2 that ends to scan for the third time are the exposed lines of enabling exposure, thereby 5 exposed lines in 6 lines of the line LN 3 that ends to scan for the third time are activated to expose.This is as the circulation from LN 1 to LN 6 of scanning for the first time, is first scan cycle (in 6 lines of exposure 5).Next, enable the line LN 4 that starts from scanning for the third time according to identical mode and end at 5 lines of line LN 8 of the 3rd scanning.Similarly, the 4th scan period, 5 lines in 6 lines are activated to expose.These also are first scan cycle.

In this manner, during the circulation (it is second scan cycle) from the LN 7 of scanning for the first time to the LN 5 of scanning for the second time, 6 exposed lines in 7 scan lines are activated to expose, and therefore, the intervals of on average exposing is as follows:

17.6×7÷6＝20.5

Therefore, intervals becomes about 20.5 μ m, thereby compares with first circulation, realizes 4.2% contraction.In this manner, determine the zoom ratio of the sub scanning direction of image as a whole by the frequency that second scan cycle is provided in first scan cycle.

That is to say that when being in the line of m in quantity, when realizing shrinkage operation corresponding to the interval of one time one line, the total quantity of scan line becomes { 6 ÷, 5 * (m-4)+5} line.

Because the total quantity of scan line is that (6 ÷, 5 * m) lines are so the sub scanning direction zoom ratio is as follows under the situation that does not realize described correct operation.That is:

(6÷5×(m-6)+7-6÷5×m)÷(6÷5×m)×100[％]＝-100÷6÷m[％]

In this expression formula, the processing that " 7 " indication is a unit with 7 lines will be used 6 lines in described 7 lines of " 6 " indication, and " m " indication will reduce by 1 line in every m line of view data, will use 5 lines in 6 lines of " 5 " indication.

In above-mentioned expression formula, " 6 ", " 5 " and " m " have implication same as described above.

For example, realize under 1% situation of shrinking, can realize proofreading and correct with 16.67 lines ratio once in expectation.Although the actual quantity of line is necessary for natural number, can use described ratio to come the number of times of calculation correction operation, for example,, can realize on the sub scanning direction that 1% image shrinks by in 1,667 scan line, realizing 100 correct operations.

It should be noted that: realize the switching of Figure 12 of second embodiment to 10C and Figure 11 A to controller 1027 shown in Figure 11 C and multiplexer 1030 to exposed lines shown in Figure 14 by above-mentioned Figure 10 A.Yet should note: under the situation of second embodiment, the line quantity that offers multiplexer 1030 is 7 lines.

Utilize the foregoing description, be set to be higher than the resolution ratio of the image that will be formed by the resolution ratio of lasing light emitter, and select the laser instrument that can drive for every scan line, the sub scanning direction resolution ratio of the image that will form on sheet material can be adjusted to the value of expectation.

Figure 15 is the block diagram that illustrates according to the hardware configuration of the controller 1027 of this embodiment.

Controller 1027 is provided with: the CPU 1500 of microprocessor etc., store the ROM 1501 of the program that will be carried out by CPU1500 and when carry out the RAM 1503 that the working region is provided when control is handled by CPU 1500.In addition, I/O port one 504 outputs to above-mentioned multiplexer 1030 and laser driver 1029 with control signal, and input BD signal and by the detected signal of optical sensor 1505 (after a while describe) etc.In addition, by constituting table 1502 such as the nonvolatile memory as the EEPROM of example, described table 1502 storage indication will be selected the information of which line by multiplexer 1030, wherein, and the number of times of scanning and the contraction of describing before or to expand ratio relevant.Therefore, CPU 1500 is in response to the number of times (n) of scanning and shrink or the expansion ratio instructs will select which line for each scanning to multiplexer 1030, carries out control thus, thereby forms the big or small image of expectation.

Figure 16 is the flow chart that is used to describe according to the processing of being undertaken by controller 1027 of present embodiment, and the program that is used for carrying out this processing is stored in ROM 1501, and carries out under the control of CPU 1500.It should be noted that: the description here at be the situation that a kind of color in utilizing the color of coloured image is partly carried out imaging, but for example under the situation of color-image forming apparatus for example shown in Figure 1, carry out described imaging for each color among Y, M, C and the Bk.

At first, at step S1, acquisition will be at the compression or the expansion ratio of the image that forms subsequently.Before imaging, pre-determine the contraction ratio or the expansion ratio of image.Then, process proceeds to step S2, and the variable n (providing at RAM 1503) that is used for scanning times is counted is set to " 1 ".Then, process proceeds to step S3, sends into to wait and begins to carry out imaging by beginning to carry out every type the rotation driving of motor and sheet material.Then, process proceeds to step S4, comes reference table 1502 based on the contraction ratio of the image that obtains at step S1 or the value of expansion ratio and variable n, then, determines to enable the line of laser scans subsequently, and gives multiplexer 1030 with it.Then, at step S5, the view data of the line that will form in scanning next time is output to FIFO 1028.In this manner, read the view data that is stored in the FIFO 1028 with BD signal synchronised ground from FIFO1028, and described view data is sent to laser driver 1029 via multiplexer 1030.In this manner, come irradiating laser, and on corresponding photosensitive drums, form the image of a plurality of line parts abreast by scanner unit.When forming the image of a main scanning in this manner, process proceeds to step S6, and adds the variable n that scanning times is counted to 1.Then, at step S7, carry out about for example whether having finished the inspection for the imaging of one page, if do not finish as yet, then process is returned step S4, and repeats above-mentioned processing.

It should be noted that: for the image that is formed by the imaging mechanism according to the imaging device of this embodiment, ROM 1501 or table 1502 also can be stored the data of the undulate quantity of size on the indication sub scanning direction, wherein said undulate quantity varying cyclically.

In this manner, by according to these undulate quantities the line that will be selected for imaging being switched, can form the image that undulate quantity is corrected at step S4.

In addition, for example optical sensor 1505 can be set, be used for detecting the undulate quantity of size on the sub scanning direction, described undulate quantity varying cyclically at the image that forms by imaging mechanism according to the imaging device of this embodiment.By at above-mentioned steps S4 with reference to the undulate quantity that detects by optical sensor 1505, and switch being selected for the line that carries out imaging according to described undulate quantity, can form the image that undulate quantity is corrected.

Carry out imaging by scan in this manner the line that is used for imaging switched at every turn, can on sheet material, form the image of zoom ratio with expectation.

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 will be given the most wide in range explanation, thereby comprise all described improvement and equivalent configurations and function.

Claims

1. one kind is used to use electrophotographic method to come the imaging device of imaging, and it comprises:

Scanning element, this scanning element has a plurality of laser components, and it can scan many lines along sub scanning direction abreast with second resolution ratio, and described second resolution ratio is higher than first resolution ratio of the image that will form along main scanning direction,

The zoom ratio setting device is used for being provided with along the zoom ratio of the image of sub scanning direction in response to first and second resolution ratio and the image size that is used for imaging,

Driving control device is used for carrying out control in response to the zoom ratio that is provided with by described zoom ratio setting device, thereby selects and drive any laser component in a plurality of laser components of described scanning element, and

Imaging device is used on print media forming the image of line, and wherein, described line uses laser component scanning by described scanning element, and wherein, described laser component is by described drive control device drives.

2. equipment as claimed in claim 1, wherein, described zoom ratio setting device is provided with zoom ratio, thereby the main scanning direction resolution ratio of the image that is formed is become identical with sub scanning direction resolution ratio.

3. equipment as claimed in claim 1, wherein, described zoom ratio setting device is provided with zoom ratio in response to the expansion/contraction ratio of print media.

4. equipment as claimed in claim 1 also comprises: storage device, be used for the data of undulate quantity of the sub scanning direction epigraph size of the image that storage representation forms by described imaging device, and described undulate quantity varying cyclically,

Wherein, described zoom ratio setting device is provided with zoom ratio in response to the data by described memory device stores.

5. equipment as claimed in claim 1 also comprises: checkout gear, be used to detect the undulate quantity of the sub scanning direction epigraph size of the image that forms by described imaging device, and described undulate quantity varying cyclically,

Wherein, described zoom ratio setting device is provided with zoom ratio in response to the undulate quantity that is detected by described checkout gear.

6. as the described equipment of any one claim among the claim 1-5, also comprise: the device that is used to store following data, the indication of described data will be selected which laser component in a plurality of laser components in response to zoom ratio and scanning times, wherein, described driving control device is selected driven one or more laser components with reference to the data of storage.

7. imaging device comprises:

The distance between centers of tracks adjusting device, be connected with the spacing that receives view data and be used to adjust the spacing of scan line and adjust data, it is used for control view data is applied to described a plurality of scan line generation part, thereby the view data of two continuous lines of view data is applied to scan line and produces part, and each bar scan line that this scan line produces part is spaced apart the interval different with the distance between centers of tracks of view data.

8. equipment as claimed in claim 7, wherein, described distance between centers of tracks adjusting device can be operated in first scan cycle, be applied to scan line with view data and produce part two continuous lines, this scan line produces the scan line that each bar scan line spacings is partly opened first predetermined quantity, and described distance between centers of tracks adjusting device can be operated in second scan cycle, be applied to scan line with the view data with two continuous lines and produce part, this scan line produces the scan line that each bar scan line spacings is partly opened second predetermined quantity that is different from first predetermined quantity.

9. equipment as claimed in claim 8 wherein, is provided with first predetermined quantity according to the ratio of the distance between centers of tracks of preset space length and view data.

10. equipment as claimed in claim 8 or 9, wherein, second predetermined quantity and first predetermined quantity differ 1.

11. equipment as claimed in claim 7, wherein, described distance between centers of tracks adjusting device can be operated in first scan cycle, the M scan line that is applied in (M+k) scan line generation part with the view data with M bar continuous lines produces part, it is adjacent one another are that described M scan line produces each bar scan line partly, and described distance between centers of tracks adjusting device can be operated in second scan cycle, the N scan line that is applied in (N+k) scan line generation part with the view data with N bar continuous lines produces part, it is adjacent one another are that described N scan line produces each bar scan line partly, wherein, M is different from N, and k is a natural number.

12. equipment as claimed in claim 11 wherein, is provided with M and k according to the ratio of the distance between centers of tracks of preset space length and view data.

13. equipment as claimed in claim 7, wherein, spacing is adjusted the relative frequency that data are used for determining first scan cycle and second scan cycle.

14. equipment as claimed in claim 7, wherein, spacing adjust data be set in the compensating image device machinery or other error.

15. equipment as claimed in claim 7, it can be used to carry out first imaging operation that is used at first enterprising line item of recording medium, carry out second imaging operation that is used at second enterprising line item of recording medium thereafter, wherein, spacing is adjusted the error that condition that data are set to be used for to compensate the recording medium after first imaging operation changes caused second imaging operation.