JP4513431B2 - Image forming apparatus and method - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer, and in particular, an image forming apparatus effective in a mode for outputting an image forming job in which various image images such as a full-color image and a single-color image are mixed at high speed and its It relates to the improvement of the method.

In recent years, in an image forming apparatus using an electrophotographic system, printing speed has been further increased as image quality has been improved. Particularly, in the on-demand printing method, each component of the image forming apparatus is used to output an image forming job in which various image images such as a full color image or a single color image (for example, a single color K image: a single color black image) are mixed at high speed. Particularly, the developing device is always forced to be in an image forming state.
Under such circumstances, in particular, when the developing device continues to drive an image image with a low image density, the replacement of the developer (toner) in the developing device is small, and the deterioration of the developer is promoted. Then, an aggregate of toners is generated. If the toner aggregate is accumulated in the developing device and is discharged onto the image when a high image density image is output later, there is a concern that a portion corresponding to the toner aggregate becomes a white defect.

Therefore, for example, in an image forming apparatus of a tandem type intermediate transfer system using an intermediate transfer belt (IBT belt), each color component image of yellow (Y), magenta (M), cyan (C), and black (K). As the forming unit, a corresponding color component developing device is provided for each photosensitive drum. However, for example, when a monochrome K image is formed in an incoming image forming job, as shown in FIG. In addition, the developing roll of an unused color developing device (in this example, each YMC developing device) is stopped during the image forming job to prevent the deterioration of the developer in the developing device and the generation of toner aggregates as much as possible. It has been.
In such an image forming job method, the development roll can be stopped after the image quality adjustment inter-image patch (IIP) is formed immediately before the image forming area and immediately after the image forming area. When the IIP image is formed in the inter-image area, the range is limited to a range in which it can be returned to a state where it can be driven at the normal rotation speed.

JP 2002-23451 A (Embodiment of the Invention, FIG. 6)

  However, in such an image forming job method, if attention is paid to the development nip region of the developing device once stopped, that is, the opposite portion between the developing roll and the photosensitive drum once stopped, the charged charge of the toner in the development nip region is developed. Since the toner flows and disappears to the photosensitive drum side when the roll is stopped, the toner band in which the charged charge disappears adheres to the photosensitive drum side in the next drive of the developing device regardless of the control electric field. The phenomenon will occur. The toner band Tm is transferred from the photosensitive drum to the intermediate transfer belt (IBT belt), and as a result, appears as a stain on the monochrome K image.

In order to solve such a technical problem, for example, the prior art disclosed in Patent Document 1 has already been proposed.
As shown in FIG. 14, a skip panel (empty image panel) is provided in front of an image panel corresponding to a single color K image (single color K image panel). Stop and use the toner ejection patch imaged in the inter-image area immediately before the monochrome K image panel, transfer the toner in the development nip area that was sufficiently stopped by the skip panel to the photosensitive drum side, and The patch image is cleaned.
According to this aspect, as a result, the monochrome K image portion is prevented from being stained with the toner band.
However, since the system includes a skip panel, there is a concern that productivity may be reduced accordingly. In particular, in the duplex recording mode (Duplex Mode), because the front and back are aligned, as a result, two skip panels are required on the front and rear surfaces of the monochrome K image panel.

  The present invention has been made to solve the above technical problem, and effectively reduces stress on a developer for a color developing device that is not used while suppressing a decrease in productivity. The present invention provides an image forming apparatus and a method thereof.

That is, the present invention is, as shown in FIG. 1, a plurality of image forming carrier 2 which each color component images respectively formed separately supported (e.g. 2 a to 2 d), are formed on the respective image forming carrier 2 The intermediate transfer member 3 that primarily transfers each color component image and then secondarily transfers it to the recording material 4, and latent image forming means 6 that forms each color component electrostatic latent image on each image forming carrier 2 (for example, 6a to 6d). a), visible images of each color component electrostatic latent image formed on the image-forming carrier 2 opposite each of the developer has a carrier and the image forming bearing member 2 by the corresponding color component developer A plurality of developing means 7 (7a to 7d), and an image forming control means 8 for performing image forming control on the image forming carrier 2 , the latent image forming means 6 and the developing means 7 based on predetermined color component image information. with the door, the image formation control unit 8 determines whether the supply of each color component image information for image forming job A constant section 11, in the normal mode with a speed which is accelerated from the speed of the corresponding image forming carrier 2 with respect to the developer carrying member of the developing means 7 among color component image data of the image forming job is fed (e.g., 7d) An image forming carrier corresponding at least in the image forming region to the developer carrying member of the normal developing control means 12 for driving control and the developing means 7 (for example, 7a to 7c) to which color component image information is not supplied in the image forming job. And a special development control means 13 for performing deceleration control so as to reduce the speed to 2 or less .
1 illustrates a tandem type intermediate transfer type image forming apparatus. In this embodiment, the image carrier 1 includes a plurality of image forming carriers 2 that individually form and carry each color component image (for example, 2a to 2d) and the respective color component images formed on the respective image forming carriers 2 are primarily transferred via the primary transfer means 3a to 3d and then secondarily transferred to the recording material 4 via the secondary transfer means 3e. An intermediate transfer member 3 is provided .

In such technical means, the object of application of the image forming apparatus of this case is an image forming apparatus of a tandem type intermediate transfer system, but a tandem type recording material conveying system or a four-cycle type developing unit is used. The present invention can also be applied to a mode in which they are arranged in parallel.
The latent image forming means 6 may be a combination of a charging means and an exposure means, or a combination of a charging means and an ion flow recording head, as long as an electrostatic latent image can be formed on the image forming carrier 2. However, it may be selected as appropriate.
Further, as the developing means 7, as long as the electrostatic latent image on the image forming carrier 2 is visualized with each color component developer, for example, the developing method is limited to the two-component developing method. Instead, it can be selected as appropriate.

The image forming control unit 8 may be any unit that performs image forming control on the image forming carrier 2 , the latent image forming unit 6, and the developing unit 7 based on predetermined color component image information. Of course, if there is an image forming device, the image forming control means 8 performs predetermined image forming control on these devices.
Here, the predetermined color component image information may be given in advance, but an aspect including an image analysis unit that decomposes an image to be produced into each color component image information (for example, an aspect equipped with a scanner) ), The image formation control means 8 may perform image formation control based on each color component image information from the image analysis means.

Further, the image forming control unit 8 requires a determining unit 11 that determines whether or not each color component image information is supplied to the image forming job. A typical example of this type of determination unit 11 is a unit that determines whether or not each color component image information is supplied to an image forming job in accordance with a selection operation of a mode selection unit that selects an image forming mode. Widely includes other things.
Further, with respect to the normal development control means 12, it is natural that the normal processing function is realized with respect to the development means 7, and the normal processing function by the previous development control means may be followed as it is.

Furthermore, the special development control means 13 has a function of “decelerating control below the speed of the corresponding image forming carrier 2 at least in the image forming region ” with respect to the developer carrier of the developing means 7 of the color not used. Just do it.
Here, if the developer carrying member of the developing means 7 to be controlled is controlled to be decelerated, the degree of deterioration of the developer in the developing means 7 can be reduced. Therefore, there is little possibility that the charged charge of the developer disappears.
Further, as a typical mode of the deceleration control, at least the developer carrying member facing the image forming carrier 2 in the developing means 7 to be subjected to the deceleration control may be controlled. At this time, "at least the deceleration control of the developer carrier" is a mode in which only the developer carrier is controlled to be decelerated, in addition to a method of integrally driving a developer stirring member in addition to the developer carrier, This is intended to include a mode in which development of other members including the developer carrier is also controlled.

Further, as a preferable deceleration control timing of the target developing unit, there is a timing at which the target developing unit starts deceleration control after the image formation adjustment mark image formed in the inter image area immediately before the target image forming area is formed. It is done. In this way, consideration can be given so as not to hinder the image formation of the image adjustment mark. Note that the image formation adjustment marks referred to here include image quality adjustment patches, position adjustment ladder marks, and the like.
Further, as a preferable acceleration return timing of the developing unit 7 to be processed, the target developing unit 7 is subjected to deceleration control, and then the target image forming adjustment mark formed in the inter image area immediately after the target image forming area is subjected to the target For example, the developing unit 7 may accelerate the target developing unit 7 to achieve steady driving.
Furthermore, as a preferable deceleration and acceleration control timing of the developing unit 7 to be processed, the developer formed on the developer carrying member of the target developing unit 7 is formed in the inter image area immediately before the image forming area. Deceleration control is started after image formation of the image adjustment mark, and acceleration return to the normal mode is performed in the interimage area immediately after the image formation area before image formation of the image adjustment mark formed in the interimage area. Things.

Further, as a more preferable aspect of the special development control means 13, there is one that further variably controls the development bias with respect to the development means to which the color component image information is not supplied in the image forming job.
At this time, as a typical mode of variable control of the development bias, the development bias is variably controlled so that the DC bias component of the development bias is lower than the development bias in the normal mode. It is preferable to start the variable control of the developing bias after the start of the deceleration control and return the developing bias to the normal mode state before the end of the deceleration control to the developer carrier. It is preferable that the DC bias component is variably set so that the differential voltage between the background voltage of the electrostatic latent image and the DC bias is larger than that in the normal mode. According to this aspect, at the start of the next drive, the transfer of the toner band is more reliably prevented in that the differential voltage functions to suppress the transfer of the toner in the development nip area to the image carrier 1 side. Is done.

Further, the present invention is not limited to the above-described image forming apparatus, and the image forming control procedure of the image forming control unit 8 can be grasped in time series and can be grasped as the following image forming method.
That is, in this case, as an image forming method according to the present invention, as shown in FIG. 1, a plurality of image forming carriers 2 (for example, 2a to 2d) for individually forming and supporting each color component image, and each image forming An intermediate transfer body 3 for primary transfer of each color component image formed on the carrier 2 and then secondary transfer to the recording material 4, and a latent image forming means for forming each color component electrostatic latent image on the image forming carrier 2 6 (for example, 6a to 6d) and each color component electrostatic latent image formed on the image forming carrier 2 having a developer carrying member facing each image forming carrier 2 and corresponding color component development In an image forming method using a plurality of developing means 7 (7a to 7d) for visualizing with an agent, after determining whether or not each color component image information is supplied to the image forming job, the color of the image forming job developer carrying of the developing means 7 (e.g., 7d) of component image information is supplied Corresponding to drive control in the normal mode with a speed which is accelerated from the speed of the image forming carrier 2, the developer carrying member of a developing means among color component image data of the image forming job is not supplied (e.g., 7 a to 7 c) to On the other hand, at least in the image forming area, the deceleration control may be performed so as to reduce the speed to the speed of the corresponding image forming carrier 2 or less .
For example, as shown in FIG. 2, when the full color mode is selected, all the developing means 7 (7a to 7d) are driven and controlled in the normal mode (for example, the speed v = v1 of the developer carrying member), whereas the single color is selected. When the K mode is selected, the black developing means 7 (for example, 7d) to be used is driven in the normal mode, and at least an image corresponding to the unused YMC developing means 7 (7a to 7c) in the image forming area. What is necessary is just to perform the special mode (v = v2: v2 <v1) which carries out deceleration control so that it may decelerate below the speed of a formation support body . Of course, the development bias may be variably controlled in the special mode.

According to the present invention, after determining whether or not each color component image information is supplied to the image forming job, drive control is performed in the normal mode for the developer carrier of the developing unit to which the color component image information is supplied in the image forming job. In addition, since the developer carrying member of the developing means to which the color component image information is not supplied in the image forming job is controlled to decelerate below the speed of the corresponding image forming carrier at least in the image forming region, the full color image Even for an image forming job in which various image images such as a single color image and the like are mixed, an image forming process can be performed efficiently and without image smearing.
In particular, in the present invention, the special mode controlled to be decelerated from the normal mode is used for the developer carrying member of the developing unit of the unused color, so that the stress on the developer in the developing unit of the unused color is reduced. This can effectively suppress the deterioration of the developer.
Furthermore, in the present invention, it is not necessary to adopt a temporary stop method or a temporary stop method using a skip panel for the developing means of unused colors, so that the toner in the development nip region is suppressed while suppressing a decrease in productivity. As a result, it is possible to effectively prevent image contamination due to the toner band.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
Embodiment 1
FIG. 3 shows Embodiment 1 of an image forming apparatus to which the present invention is applied.
In the figure, an image forming apparatus uses, for example, four color components (in this embodiment, yellow (Y), magenta (M), cyan (C), black (K)) images (toner images) by electrophotography. The image forming unit 20 (20a to 20d) that forms the image, the intermediate transfer belt 30 that sequentially transfers (primary transfer) each color component image formed by each image forming unit 20, and the intermediate transfer belt 30. The batch transfer device 50 that batch-transfers (secondary transfer) the superimposed image to the paper (recording material) 100, the belt cleaner 60 that removes residual toner on the intermediate transfer belt 30, and the batch-transferred image on the paper 100. And a fixing device 70 for fixing the toner image.
According to the present embodiment, the respective color component toner images formed by the respective image forming units 20 are sequentially transferred to the intermediate transfer belt 30, and the superimposed toner images on the intermediate transfer belt 30 are collectively transferred to the paper 100, and then the fixing device. While fixing at 70, residual toner on the intermediate transfer belt 30 is removed by a belt cleaner 60.

  In the present embodiment, each image forming unit 20 (20a to 20d) has a photosensitive drum 21 (specifically, 21a to 21d), and around each photosensitive drum 21, the photosensitive drum 21 is provided. A charging device 22 (specifically, 22a to 22d) such as a corotron, and a laser scanning device (ROS: Raster Output Scanner) for writing an electrostatic latent image on the charged photosensitive drum 21. An exposure device 23 (specifically 23a to 23d), a developing device 24 (specifically 24a to 24d) for developing the electrostatic latent image written on the photosensitive drum 21 with each color component toner, A primary transfer device 25 (specifically, 25a to 25d) such as a transfer roll for transferring a toner image on the photosensitive drum 21 to the intermediate transfer belt 30 and a drum cartridge from which residual toner on the photosensitive drum 21 is removed. (Specifically 26a to 26d) over Na 26 is obtained by respectively disposed.

Further, the intermediate transfer belt 30 is stretched around a plurality of (in this embodiment, five) stretching rolls 31 to 35. In this embodiment, the tension roll 31 is used as a drive roll driven by a belt drive motor (not shown), the tension rolls 32 and 35 are used as driven rolls, and the tension roll 33 Is used as a correction roll for controlling meandering in a direction substantially perpendicular to the moving direction of the intermediate transfer belt 30 (steering roll: provided so as to be tiltable with one end in the axial direction as a fulcrum), and a tension roll 34 will be described later. And used as a backup roll for the batch transfer device 50.
Further, in the present embodiment, as shown in FIG. 3, the batch transfer device 50 is disposed on the surface side of the intermediate transfer belt 30 so as to be retractable and is grounded, and is opposed to the transfer roll 51. A backup roll 52 (also used as the stretching roll 34 in the present embodiment) provided at a portion to be operated, and a bias roll 53 that is disposed in contact with the backup roll 52 and to which a predetermined DC bias is applied. .
In the present embodiment, the belt cleaner 60 is retractably provided at a position corresponding to the stretching rolls 31 and 35, and a conductive fur brush 61 is disposed at a position corresponding to the stretching roll 35. The blade 62 is disposed at a location corresponding to the stretching roll 31.

In this embodiment, the sheet 100 enters the transfer area of the batch transfer apparatus 50 (corresponding to the nip area between the transfer roll 51 and the backup roll 52) through the guide chute 101.
On the other hand, on the downstream side of the batch transfer device 50, an outlet side guide chute 102 is inclined, and a plurality of conveying belts 103 are disposed between the outlet side guide chute 102 and the fixing device 70, for example. The paper 100 that has passed through the transfer device 50 is guided to the fixing device 70 through the exit side guide chute 102 and the conveying belt 103.
Further, in the present embodiment, the fixing device 70 has a roll pair configuration including a heating roll 71 and a pressure roll 72, and the periphery is covered by a case 73 having openings on the inlet side and the outlet side of the paper 100. It has been broken.

In the present embodiment, each color component (YMCK) developing device 24 (24a to 24d) is opened facing the photosensitive drum 21 and contains developer G therein as shown in FIG. A developing roll 41 is disposed at a portion facing the opening of the developing housing 40, and developer agitating augers 42 and 43 are disposed on the back side of the developing roll 41, for example, vertically. Further, a partition plate 46 in which the developer stirring augers 42 and 43 are vertically divided is provided in the developing housing 41, and communication openings 45a and 45b (see FIG. 5) are opened at both ends of the partition plate 46. Thus, a developer circulation path 45 in two upper and lower stages is provided. Reference numeral 44 denotes a layer thickness regulating plate that regulates the layer thickness of the developer G on the developing roll 41, and reference numeral 47 denotes a transport auger that guides the developer G detached from the developing roll 41 to the developer stirring auger 43 side.
Here, in the present embodiment, the developing roll 41 includes a rotatable developing sleeve 41a and a magnet roll that is fixedly disposed inside the developing sleeve 41a and has a plurality of magnetic poles arranged in a predetermined pattern. 41b.
A driving force from a driving motor 81 is transmitted to the developing sleeve 41a via a driving transmission system 82 such as a gear train. A developing bias from a bias power source 83 is applied to the developing sleeve 41a. It is to be applied. In this example, the developing bias is composed of a DC component superimposed with an AC component, and the DC component and the peak-to-peak voltage of the AC component are variably set.

  Further, as the drive transmission system 82 of the developing device 24, for example, as shown in FIG. 5A, a drive input shaft 821 to which a drive force from a drive motor 81 is input is input to the drive input shaft 821. The driving force thus transmitted is transmitted to the developing roll 41 and the developer agitating augers 42 and 43 via the transmission gear train 822, or input to the driving input shaft 821 as shown in FIG. The driving force thus transmitted is transmitted to the developing roll 41 and the developer agitating augers 42 and 43 via the transmission gear train 822, and the driving force can be transmitted only to the developing roll 41 via the clutch 823. 5 (c), it has a plurality of drive input shafts 821, 825, and transmits the driving force from one of the drive input shafts 821 to the developer stirring augers 42, 43 via the transmission gear train 822, other Aspects as the driving force from the drive input shaft 825 directly or via the unillustrated transmission gear train transmits to the developing roller 41 and the like.

  Further, as shown in FIG. 6, in the present embodiment, the image forming apparatus is provided with an image forming control device 90 that controls each image forming unit 20, the intermediate transfer belt 30, a paper conveyance system, and the like. Yes. The image forming control device 90 is constituted by a microcomputer system including, for example, a CPU, a ROM, a RAM, and an I / O port, and an image forming processing program (for example, FIG. 7 (including a development control processing program shown in FIG. 7) is incorporated in the ROM in advance, an input signal from a UI (user interface) 91 is fetched into the CPU, and the image creation processing program is executed by the CPU. A signal is generated and sent to the charging controller 92 for controlling the charging device 22, the ROS controller 93 for controlling the exposure device 23, the developing roll drive controller 94, the developing bias controller 95, the primary transfer bias controller 96, the secondary transfer bias controller 97, and the like. Each control signal is transmitted.

Next, the operation of the image forming apparatus according to the present embodiment will be described.
In the present embodiment, it is assumed that a mode selection switch capable of selecting a full color mode, a single color mode (for example, a single color K mode), a two color mode, or the like is provided on the UI 91.
If the full color mode is selected now, the image forming control device 90 executes the normal mode for each developing device 24 (Y, M, C, K) as shown in FIG.
In this embodiment, FIG. 8 shows a timing chart of the image forming process. An image (MCK image (full color image), monochromatic K image) corresponding to each image forming mode on the intermediate transfer belt (IBT belt). ) Show the panel.
Here, the normal mode indicates an image forming process corresponding to the YMCK image panel of FIG. 8. For each developing device 24, for example, as shown in FIG. And a predetermined level of developing bias VB (see FIG. 4) is applied. The peripheral speed v1 of the developing roll 41 in the normal mode is set to be higher than the peripheral speed vp of the photosensitive drum 21.

Next, assuming that a single color mode (for example, single color) is selected, the image forming control device 90 executes the normal mode for the used developing device 24 (K) as shown in FIG. YMC) special mode is executed.
In the present embodiment, the special mode indicates an image forming process corresponding to the monochrome K image panel of FIG. 8, and the used developing device 24 (K) is, for example, as shown in FIG. While the developing roll 41 is rotated at the peripheral speed v1 and the developing bias VB of a predetermined level is applied, the non-use developing device 24 (YMC) is, for example, as shown in FIG. Is decelerated to a peripheral speed v2 ( v2 <v1 ), and the developing bias VB is reduced by about 10 to 50 V with respect to the standard developing bias.

In such a special mode, the developing roll 41 of the developing device 24 (YMC) is set to be decelerated compared to the normal mode. However, due to the difference in the drive transmission system 82 as shown in FIGS. The entire developing device including the developing roll 41 may be decelerated, or only the developing roll 41 may be decelerated.
In the special mode, the deceleration range of the developing roll 41 is from immediately after the image forming adjustment patch (inter image patch: IIP) is formed in the inter image area immediately before the monochrome K image panel to after a predetermined time has elapsed. After decelerating the roll 41, it is necessary to return to acceleration so that it can be recovered to the normal rotational speed at the start of IIP imaging in the inter-image area immediately after the monochrome K image panel.

  As described above, when the developing roll 41 is decelerated, the degree of deterioration of the developer in the developing nip region is suppressed to a smaller level than in the normal mode, and the developer G does not stay in the developing nip region. In addition, a situation in which the charged charge of the toner constituting the developer G in the development nip area disappears to the photosensitive drum 21 side is effectively avoided. In this regard, as shown in FIG. 9C, in the temporary stopping method of the developing roll 41, the charged charge e of the toner constituting the developer G in the developing nip area disappears to the photosensitive drum 21 side. Although there is a concern that image smearing occurs due to toner band transfer, if the special mode is performed as in the present embodiment, image smearing phenomenon due to toner band transfer can be effectively prevented. .

In the present embodiment, in the special mode, the development bias VB is reduced compared to the normal mode. Therefore, as shown in FIG. 10A, the differential voltage ΔV between the background portion potential VH and the development bias VB is normal. It is set larger than the mode. As shown in FIGS. 10A and 10B, the differential voltage ΔV works as a force for preventing the toner on the developing roll 41 from transferring to the electrostatic latent image image portion potential VL on the photosensitive drum 21 side. The situation in which the toner is transferred to the photosensitive drum 21 as the fog toner is effectively suppressed.
A preferable value of the differential voltage ΔV is 90 to 150 V in the normal mode, but may be set to about 100 to 200 V in the special mode.

  Further, when a two-color mode (for example, RK mode) such as red (Red), for example, is selected, the image forming control device 90 uses the developing device 24 (R (Y, M) as shown in FIG. ) The normal mode may be executed for K) and the special mode may be executed for the unused developing device 24 (C).

In the present embodiment, only the direct current component is variably set for the developing bias VB. In addition to this, or alternatively, the alternating current component may be variably set.
Here, regarding the AC component variable control, for example, in the special mode, the peak-to-peak voltage may be set larger than that in the normal mode. In this case, since the movement of the toner of the developer in the development nip area is activated, each toner is preferable in that the fog toner is suppressed according to the background potential.
In this embodiment, a method of variably setting the developing bias VB is adopted. However, as shown in FIG. 11, in the special mode, only the deceleration control is performed for the unused developing device 24 (YMC), and the developing bias is set. Of course, VB may be the same as in the normal mode.

In this example, the image forming apparatus model according to Embodiment 1 is used, and the developing roll speed (photosensitive drum ratio) is changed as a parameter. Deterioration and toner aggregation formation were examined.
In this example, the experimental conditions are as follows.
Photosensitive drum peripheral speed: 351 mm / sec.
Gap between the photosensitive drum and the developing roll: 0.35 mm
Surface potential of photosensitive drum: 670V
Development bias: 550V
In addition, regarding the evaluation of the toner fog band failure, the mark is “X” if the toner band is visible, and “◯” if the toner band is not visible. On the other hand, the roughness of patch images was visually evaluated for developer deterioration, and the number of aggregates per unit weight was counted and evaluated for toner aggregation. If the number is 10 or less per gram, the result is ◯, 10 to 20 is Δ, and 20 or more is ×.
The evaluation result by an Example is shown in FIG.
According to the figure, as for the toner fog band failure, for example, when the developing roll of the developing device (YMC) is stopped in the single color K mode, the toner fog band failure is observed. The initial value of the developing roll speed is 1.75 in the drum ratio, and when the developing roll is sequentially reduced in the special mode, even if the developing roll speed is reduced to about 0.5, no toner fog band failure is seen at all. It was.
As for developer deterioration and toner agglomeration, the initial value of the developing roll speed was set to 1.75 based on the ratio of the photosensitive drum, and when this was sequentially reduced, the developing roll speed started from around 1.0 or less. Deterioration and toner aggregation were no longer observed.
Therefore, it can be understood that, in order to satisfy both of the toner fog band obstacle, the developer deterioration, and the toner aggregation generation, the deceleration rate of the developing roll may be set in a good region of FIG.

1 is an explanatory diagram showing an outline of an image forming apparatus according to the present invention. It is explanatory drawing which shows the effect | action of the image forming apparatus which concerns on this invention. 1 is an explanatory diagram showing an overall configuration of an embodiment of an image forming apparatus according to the present invention. It is explanatory drawing which shows the detail of the image development apparatus used by this Embodiment. (A)-(c) is explanatory drawing which shows the drive transmission system of a developing device. 3 is an explanatory diagram illustrating a control system of the image forming apparatus according to the embodiment. FIG. It is explanatory drawing which shows the content of the development control processing of the control system used by embodiment. 6 is a timing chart illustrating the operation of the image forming apparatus according to the embodiment. (A) (b) is explanatory drawing which shows the operating state of the developing device used by embodiment, (b) is explanatory drawing which shows the operating state of the developing device used by the comparison form. (A) is explanatory drawing which shows typically the developing bias control of the developing device used by embodiment, (b) is explanatory drawing which shows the principle of operation. 6 is a timing chart illustrating an operation of the image forming apparatus according to a modification of the embodiment. It is explanatory drawing which shows evaluation about the deceleration control of the image development apparatus used in an Example. 6 is a timing chart showing the operation of a conventional image forming apparatus. 10 is a timing chart showing the operation of another conventional image forming apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 (2a-2d) ... Image formation carrier, 3 ... Intermediate transfer body, 3a-3d ... Primary transfer means, 3e ... Secondary transfer means, 4 ... Recording material, 6 (6a-6d) ... Latent image forming means, 7 (7a to 7d) ... Developing means, 8 ... Image forming control means, 11 ... Determining means, 12 ... Normal developing control means, 13 ... Special developing control means

Claims (10)

A plurality of image forming carriers for forming and supporting each color component image individually ;
An intermediate transfer body for primary transfer of each color component image formed on each image forming carrier and then secondary transfer to a recording material;
Latent image forming means for forming each color component electrostatic latent image on each image forming carrier;
A plurality of developments each having a developer carrying member facing each image forming carrier and visualizing each color component electrostatic latent image formed on the image forming carrier with a corresponding color component developer Means,
An image forming control unit that performs image forming control on the image forming carrier, the latent image forming unit, and the developing unit based on predetermined color component image information ;
The image formation control means
Determining means for determining whether or not each color component image information is supplied to the image forming job;
Normal development control means for controlling driving in a normal mode having a speed accelerated from the speed of the corresponding image forming carrier with respect to the developer carrier of the developing means to which color component image information is supplied in the image forming job;
Special development control means for performing deceleration control so that the developer carrying body of the developing means to which color component image information is not supplied among image forming jobs is decelerated to be equal to or lower than the speed of the corresponding image forming carrier at least in the image forming area. An image forming apparatus comprising the image forming apparatus. The image forming apparatus according to claim 1.
Image analysis means for decomposing the image to be produced into each color component image information;
An image forming apparatus, wherein the image forming control unit performs image forming control based on each color component image information from the image analyzing unit. The image forming apparatus according to claim 1.
The image forming apparatus characterized in that the special development control means further variably controls the development bias for the development means to which color component image information is not supplied in the image forming job. The image forming apparatus according to claim 3.
The special development control means variably controls the development bias so that the DC bias component of the development bias is lower than the development bias in the normal mode for the development means to which the color component image information is not supplied in the image forming job. Further, the development bias variable control is started after the deceleration control to the developer carrier is started, and the development bias is returned to the normal mode state before the deceleration control to the developer carrier is completed. An image forming apparatus. The image forming apparatus according to claim 3 .
The development bias variable control by the special development control means is characterized in that the DC bias component is variably set so that the differential voltage between the background voltage of the electrostatic latent image and the DC bias is larger than that in the normal mode. Image forming apparatus. The image forming apparatus according to claim 1.
The special development control means starts deceleration control on the developer carrying member of the target developing means after the image forming adjustment mark formed in the inter image area immediately before the target image forming area is formed. Image forming apparatus. The image forming apparatus according to claim 1.
Special development control means, after deceleration control the developer carrying member of the subject developing means, when the image formation of the mark imaging adjustments formed in inter image area immediately after the target imaging region of the subject developing means a developer carrying body image forming apparatus characterized by accelerates returning the developer carrying member of the subject developing means to achieve the drive stationary. The image forming apparatus according to claim 1.
The special development control means is for image forming adjustment formed in the inter image area immediately before the image forming area for the developer carrier of the developing means to which color component image information is not supplied in the image forming job. Deceleration control is started after image formation of the mark, and acceleration is returned to the normal mode in the interimage area immediately after the image formation area before image formation of the image adjustment mark formed in the interimage area. An image forming apparatus. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the determination unit determines whether or not each color component image information is supplied to an image forming job in accordance with a selection operation of a mode selection unit that selects an image forming mode. A plurality of image forming carriers for forming and supporting each color component image individually ;
An intermediate transfer body for primary transfer of each color component image formed on each image forming carrier and then secondary transfer to a recording material;
Latent image forming means for forming each color component electrostatic latent image on each image forming carrier;
A plurality of developments each having a developer carrying member facing each image forming carrier and visualizing each color component electrostatic latent image formed on the image forming carrier with a corresponding color component developer In an image forming method using the means,
After determining whether or not each color component image information is supplied to the image forming job,
In the image forming job, the developer carrying member of the developing means to which the color component image information is supplied is driven and controlled in a normal mode having a speed accelerated from the speed of the corresponding image forming carrier ,
An image characterized in that the image forming job is controlled to decelerate so that the developer carrying member of the developing means to which color component image information is not supplied is decelerated to a speed equal to or lower than the speed of the corresponding image forming carrier at least in the image forming region. Forming method.

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