JP2014122942A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of prints per unit time while discharging deteriorated developer.SOLUTION: An image forming apparatus (U) includes: width determination means (C15) for determining whether or not a width (L2) of an image (2) to be printed on a medium (S) is smaller than a width (L1) of the pre-set largest printable image; and consumption image forming means (C17) for controlling, when the width (L2) of the image (2) to be printed is smaller than the width (L1) of the largest printable image, exposure machines (ROSy to ROSk) to form an image (1) for developer consumption in an area between the width (L1) of the largest printable image and the width (L2) of the image (2) to be printed.

Description

  The present invention relates to an image forming apparatus.

  Regarding a conventional image forming apparatus, a technique described in Patent Document 1 below is known.

  In Japanese Patent Application Laid-Open No. 2010-020242 as Patent Document 1, in order to discharge the deteriorated toner from the developing unit (61), in a non-image area between the image (104) and the next image (104), A technique for forcibly consuming toner by forming a toner forced consumption pattern (105) such as a solid pattern or a halftone dot pattern is described.

Japanese Patent Laying-Open No. 2010-020242 ("0028", FIG. 5)

  An object of the present invention is to improve the number of printed sheets per unit time while discharging a deteriorated developer.

In order to solve the technical problem, an image forming apparatus according to claim 1 is provided.
An image carrier,
An exposure machine that forms a latent image on the surface of the image carrier;
A developing device for developing a latent image on the surface of the image carrier into a visible image;
A transfer device for transferring an image of the image carrier to a medium;
A fixing device for fixing the image transferred to the medium;
A width determining means for determining whether or not a width of an image printed on the medium is smaller than a preset maximum printable image width;
When the width of the image to be printed is smaller than the width of the maximum printable image, the exposure machine is controlled to control the width of the maximum printable image and the width of the image to be printed. A consumption image forming means for forming a developer consumption image in a region between
It is provided with.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect,
A deterioration determining means for determining whether or not a preset developer satisfies a deteriorated condition;
The consumption image forming means for forming an image for consumption of the developer when it is determined that the developer has deteriorated;
It is provided with.

According to a third aspect of the present invention, in the image forming apparatus according to the second aspect,
The deterioration determining means for determining that the developer has deteriorated when an image having a density lower than a preset image density is repeatedly printed;
It is provided with.

According to the first aspect of the present invention, it is possible to improve the number of printed sheets per unit time while discharging the deteriorated developer as compared with the case without the configuration of the present invention.
According to the second aspect of the present invention, wasteful consumption of the developer can be reduced as compared with the case where an image for consumption of the developer is formed even when the condition where the developer is deteriorated is not satisfied.
According to the third aspect of the present invention, it can be determined that the developer has deteriorated when an image with a small amount of developer consumption is repeatedly printed.

FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is an explanatory diagram of a main part of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the first embodiment. FIG. 4 is an explanatory diagram of an example of an image for consumption of the developer according to the first exemplary embodiment. FIG. 5 is an explanatory diagram of a flowchart of the developer deterioration measurement process of the first embodiment. FIG. 6 is an explanatory diagram of a flowchart of toner band creation processing according to the first exemplary embodiment. FIG. 7 is an explanatory diagram of an example of an image for consuming the developer according to the second embodiment, and corresponds to FIG. 4 according to the first embodiment. FIG. 8 is an explanatory diagram of a main part of the developing device according to the second embodiment.

Next, examples as specific examples of embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples.
In order to facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the up-down direction is the Z-axis direction, and arrows X, -X, Y, -Y, The direction indicated by Z and -Z or the indicated side is defined as the front side, the rear side, the right side, the left side, the upper side, the lower side, or the front side, the rear side, the right side, the left side, the upper side, and the lower side, respectively.
In the figure, “•” in “○” means an arrow heading from the back of the page to the front, and “×” in “○” is the front of the page. It means an arrow pointing from the back to the back.
In the following description using the drawings, illustrations other than members necessary for the description are omitted as appropriate for easy understanding.

(Description of Overall Configuration of Printer U of First Embodiment)
FIG. 1 is an overall explanatory view of an image forming apparatus according to Embodiment 1 of the present invention.
FIG. 2 is an explanatory diagram of a main part of the image forming apparatus according to the first embodiment of the present invention.
1 and 2, a printer U as an example of an image forming apparatus according to the first exemplary embodiment includes a printer main body U1, a feeder unit U2 as an example of a supply device that supplies a medium to the printer main body U1, and an image. A discharge unit U3 as an example of a discharge device that discharges a recorded medium, an interface module U4 as an example of a connection unit that connects between the main body U1 and the discharge unit U3, and an operation unit operated by a user And a UI.

(Description of Marking Configuration of Example 1)
1 and 2, the printer main body U1 is a print unit as an example of a control unit C that controls the printer U or an information transmission device connected to the outside of the printer U via a dedicated cable (not shown). A communication unit (not shown) that receives image information transmitted from the image server COM, a marking unit U1a as an example of an image recording unit that records an image on a medium, and the like. Connected to the print image server COM is a personal computer PC as an example of an image transmission device that is connected through a cable or a line such as a LAN (Local Area Network) and that transmits image information to be printed by the printer U. Yes.
The marking unit U1a is an example of an image holding body for printing photoconductors Py, Pm, Pc, and Pk for Y: yellow, M: magenta, C: cyan, K: black, and photographic images. A photoconductor Po for glossing the image. The photoreceptors Py to Po are composed of a photosensitive dielectric on the surface.

In FIGS. 1 and 2, around the black photosensitive member Pk, along the rotation direction of the photosensitive member Pk, a charger CCk, an exposure device ROSK as an example of a latent image forming device, a developing device Gk, and primary transfer. A primary transfer roll T1k as an example of a cleaning device and a photoreceptor cleaner CLk as an example of a cleaning device for an image carrier are disposed.
Similarly, around the other photoreceptors Py, Pm, Pc, Po, chargers CCy, CCm, CCc, CCo, exposure units ROSy, ROSm, ROSc, ROSo, developing units Gy, Gm, Gc, Go, primary Transfer rolls T1y, T1m, T1c, T1o, and photoconductor cleaners CLy, CLm, CLc, CLo are disposed.
On an upper part of the marking unit U1a, toner cartridges Ky, Kc, Km, Kk, Ko containing a developer supplied to the developing devices Gy to Go are detachably supported as an example of a storage container.

Below each of the photoconductors Py to Po, an intermediate transfer belt B, which is an example of an intermediate transfer member and an example of an image carrier, is disposed. The intermediate transfer belt B is connected to the photoconductors Py to Po and 1. It is sandwiched between the next transfer rolls T1y to T1o. The back surface of the intermediate transfer belt B includes a drive roll Rd as an example of a drive member, a tension roll Rt as an example of a tension applying member, a walking roll Rw as an example of a meandering prevention member, and a plurality of examples of a driven member. The idler roll Rf, a backup roll T2a as an example of an opposing member for secondary transfer, a plurality of retract rolls R1 as an example of a movable member, and the primary transfer rolls T1y to T1o.
On the surface of the intermediate transfer belt B, a belt cleaner CLB as an example of an intermediate transfer member cleaner is disposed in the vicinity of the drive roll Rd.

A secondary transfer roll T2b as an example of a secondary transfer member is disposed opposite to the backup roll T2a with the intermediate transfer belt B interposed therebetween. Further, a contact roll T2c as an example of a contact member is in contact with the backup roll T2a in order to apply a voltage having a polarity opposite to the charging polarity of the developer to the backup roll T2a. A conveyance belt T2e as an example of a conveyance member is stretched between the secondary transfer roll T2b of Example 1 and a drive roll T2d as an example of a drive member arranged on the lower right.
The backup roll T2a, the secondary transfer roll T2b, and the contact roll T2c constitute the secondary transfer device T2 of Example 1. The primary transfer rolls T1y to T1o, the intermediate transfer belt B, the secondary transfer device T2, and the like. Thus, the transfer devices T1, B, and T2 of Example 1 are configured.

Below the secondary transfer device T2, paper feed trays TR1 and TR2 are provided as an example of a storage unit that stores a recording sheet S as an example of a medium. A pickup roll Rp as an example of a take-out member and a separating roll Rs as an example of a separating member are disposed diagonally to the right of each sheet feeding tray TR1, TR2. A conveyance path SH that conveys the recording sheet S extends from the separation roll Rs, and a plurality of conveyance rolls Rs as an example of a conveyance member that conveys the recording sheet S to the downstream side are arranged along the conveyance path SH. Yes.
As an example of an unnecessary portion removing device, the recording sheet S is set at a preset pressure on the downstream side in the conveyance direction of the recording sheet S with respect to the position where the conveyance paths SH from the two sheet feeding trays TR1 and TR2 merge. A deburring device Bt that removes unnecessary portions of the edge of the recording sheet S, that is, a deburring device Bt is disposed.

On the downstream side of the deburring device Bt, a detection device Jk for measuring the thickness of the recording sheet S passing therethrough and detecting a state in which a plurality of recording sheets S overlap each other, so-called double feeding is disposed. A correction roll Rc that corrects an inclination with respect to the conveyance direction of the recording sheet S, that is, a so-called skew, is disposed on the downstream side of the double-feed detection device Jk as an example of a posture correction device. On the downstream side of the correction roll Rc, a registration roll Rr as an example of an adjustment member that adjusts the conveyance timing of the recording sheet S to the secondary transfer device T2 is disposed.
The feeder unit U2 is also provided with paper feed trays TR1, TR2, paper feed trays TR3, TR4, etc., which are configured in the same manner as the pick-up roll Rp, the pick-up roll Rs, and the transport roll Ra. The conveyance path SH from TR4 merges with the conveyance path SH of the main body U1 of the printer U on the upstream side of the double feed detection device Jk.

A plurality of conveying belts HB that hold the recording sheet S on the surface and convey the recording sheet S to the downstream side are arranged downstream of the conveying belt T2e in the conveying direction of the recording sheet S.
A fixing device F is disposed on the downstream side in the conveyance direction of the recording sheet S with respect to the conveyance belt HB.
A cooling device Co that cools the recording sheet S is disposed on the downstream side of the fixing device F.
On the downstream side of the cooling device Co, a decurler Hd that applies pressure to the recording sheet S to correct the curvature of the recording sheet S, that is, a so-called curl, is disposed.
An image reading device Sc that reads an image recorded on the recording sheet S is disposed on the downstream side of the decurler Hd.

A reversing path SH2 as an example of a transport path branched from the transport path SH extending toward the interface module U4 is formed on the downstream side of the image reading device Sc. A first gate GT1 as an example of the switching member is disposed.
In the reversing path SH2, a plurality of switchback rolls Rb as an example of a conveying member capable of rotating forward and reverse are arranged. On the upstream side of the switchback roll Rb, a connection path SH3 is formed as an example of a transport path that branches off from the upstream portion of the reversing path SH2 and joins the downstream side of the branch section of the transport path SH with the reversing path SH2. Has been. A second gate GT2 as an example of a transfer direction switching member is disposed at a branch portion between the reversing path SH2 and the connection path SH3.

On the downstream side of the reversing path SH2, a folding path SH4 for reversing the conveyance direction of the recording sheet S, that is, for switching back, is disposed below the cooling device Co. In the return path SH4, a switchback roll Rb as an example of a conveying member capable of rotating in the forward and reverse directions is disposed. In addition, a third gate GT3 as an example of a conveyance direction switching member is disposed at the entrance of the return path SH4.
The conveyance path SH on the downstream side of the return path SH4 merges with the conveyance paths SH of the paper feed trays TR1 and TR2.

In the interface module U4, a transport path SH extending toward the discharge unit U3 is formed.
The discharge unit U3 is provided with a stacker tray TRh as an example of a stacking container on which the recording sheets S to be discharged are stacked, and a discharge path SH5 branched from the transport path SH and extending to the stacker tray TRh is provided. Yes. In the conveyance path SH of the first embodiment, when an additional discharge unit and a post-processing device (not shown) are additionally mounted on the right side of the discharge unit U3, the recording sheet S is attached to the added device. It is configured to be transportable.

(Marking operation)
In the printer U, when image information transmitted from the personal computer PC is received via the print image server COM, a job which is an image forming operation is started. When the job is started, the photoreceptors Py to Po, the intermediate transfer belt B, and the like rotate.
The photoreceptors Py to Po are rotationally driven by a drive source (not shown).
The chargers CCy to CCo are applied with a preset voltage to charge the surfaces of the photoreceptors Py to Pk.
The exposure machines ROSy to ROSo output laser light Ly, Lm, Lc, Lk, Lo as an example of light for writing a latent image in accordance with a control signal from the control unit C, and charge the photoconductors Py to Pk. An electrostatic latent image is written on the surface.
The developing units Gy to Go develop the electrostatic latent images on the surfaces of the photoreceptors Py to Po into visible images.
The toner cartridges Ky to Ko replenish the developer consumed with the development in the developing units Gy to Go.

The primary transfer rolls T1y to T1o are applied with a primary transfer voltage having a polarity opposite to the charging polarity of the developer, and transfer the visible image on the surface of the photoreceptors Py to Po to the surface of the intermediate transfer belt B.
The photoreceptor cleaners CLy to CLo remove and clean the developer remaining on the surfaces of the photoreceptors Py to Po after the primary transfer.
When the intermediate transfer belt B passes through the primary transfer region facing the photoreceptors Py to Po, the images are transferred and stacked in the order of O, Y, M, C, and K, and then transferred to the secondary transfer unit T2. It passes through the opposing secondary transfer region Q4. In the case of a single color image, an image of only one color is transferred and sent to the secondary transfer area Q4.

The pickup roll Rp records from the paper feed trays TR1 to TR4 to which the recording sheet S is supplied according to the size of the received image information, the designation of the recording sheet S, the size and type of the stored recording sheet S, and the like. The sheet S is sent out.
The separating roll Rs separates and separates the recording sheets S sent out from the pickup roll Rp one by one.
The deburring device Bt applies a preset pressure to the passing recording sheet S to remove burrs.
The double feed detection device Jk detects the double feed of the recording sheet S by detecting the thickness of the recording sheet S passing therethrough.
The correction roll Rc corrects the skew by bringing the recording sheet S passing therethrough into contact with a wall surface (not shown).
The registration roll Rr sends out the recording sheet S in accordance with the timing when the image on the surface of the intermediate transfer belt B is sent to the secondary transfer region Q4.

The secondary transfer device T2 records the image of the intermediate transfer belt B on the recording sheet S by applying a secondary transfer voltage having the same polarity as the developer charging polarity set in advance to the backup roll T2a via the contact roll T2c. Transfer to sheet S.
The belt cleaner CLB removes the developer remaining on the surface of the intermediate transfer belt B after the image is transferred in the secondary transfer region Q4 and cleans it.
The conveying belts T2e and HB hold the recording sheet S on which the image has been transferred by the secondary transfer device T2 on the surface and convey the recording sheet S to the downstream side.

The fixing device F includes a heating roll Fh as an example of a heating member and a pressure roll Fp as an example of a pressure member, and a heater as an example of a heat source is accommodated inside the heating roll Fh. Yes. The fixing device F fixes the unfixed image on the surface of the recording sheet S by heating the recording sheet S passing through the region where the heating roll Fh and the pressure roll Fp are in contact with each other while applying pressure.
The cooling device Co cools the recording sheet S heated by the fixing device F.
The decurler Hd applies pressure to the recording sheet S that has passed through the cooling device Co to remove the curvature of the recording sheet S, so-called curl.
The image reading device Sc reads an image on the surface of the recording sheet S that has passed through the decurler Hd.

When double-sided printing is performed, the recording sheet S that has passed through the decurler Hd is transported to the reversing path SH2 by being actuated by the first gate GT1, switched back by the folding path SH4, and then passed through the transport path SH. The image is retransmitted to the registration roll Rr and printing on the second side is performed.
The recording sheet S discharged to the discharge tray TRh is transported through the transport path SH and discharged to the stacker tray TRh. At this time, when the recording sheet S is discharged to the stacker tray TRh with the front and back sides reversed, the recording sheet S is once carried into the reversing path SH2 and the rear end of the recording sheet S in the conveying direction is the second gate GT2. , The second gate GT2 is switched and the switchback roll Rb rotates in the reverse direction, and is conveyed through the connection path SH3 and conveyed to the stacker tray TRh.
On the stacker tray TRh, the recording sheets S are stacked, and the stacking plate TRh1 is automatically raised and lowered so that the uppermost surface has a preset height according to the stacking amount of the recording sheets S.

(Description of the control part of Example 1)
FIG. 3 is a block diagram illustrating the functions of the control unit of the image forming apparatus according to the first embodiment.
In FIG. 3, the control unit C of the printer main body U1 has an input / output interface I / O for inputting / outputting signals to / from the outside. In addition, the control unit C includes a ROM (read only memory) in which a program for performing necessary processing, information, and the like are stored. In addition, the control unit C includes a random access memory (RAM) for temporarily storing necessary data. The control unit C includes a central processing unit (CPU) that performs processing according to a program stored in a ROM or the like. Therefore, the control part C of Example 1 is comprised by the small information processing apparatus, what is called a microcomputer. Therefore, the control part C can implement | achieve various functions by running the program memorize | stored in ROM etc.

(Signal output element connected to the control unit C of the printer body U1)
The control unit C of the printer main body U1 receives an output signal from a signal output element such as an operation unit UI.
The operation unit UI includes a power button UI1 as an example of a power-on unit, a display panel UI2 as an example of a display unit, a numeric input unit UI3, an arrow input unit UI4, and the like.

(Controlled elements connected to the control unit C of the printer body U1)
The control unit C of the printer main body U1 is connected to a drive circuit D1 as a drive source, a power supply circuit E, and other control elements (not shown). The control unit C outputs those control signals to the circuits D1, E and the like.
D1: Drive circuit of drive source The drive circuit D1 of the drive source rotates and drives the photoreceptors Py to Po, the intermediate transfer belt B, and the like via a main motor M1 as an example of a drive source.
E: Power Supply Circuit The power supply circuit E includes a development power supply circuit Ea, a charging power supply circuit Eb, a transfer power supply circuit Ec, a fixing power supply circuit Ed, and the like.
Ea: Power supply circuit for development The power supply circuit Ea for development applies a development voltage to the development rolls of the development units Gy to Go.
Eb: Charging power supply circuit The charging power supply circuit Eb applies a charging voltage for charging the surfaces of the photoreceptors Py to Po to the chargers CCy to CCo, respectively.
Ec: Power supply circuit for transfer The power supply circuit Ec for transfer applies a transfer voltage to the primary transfer rolls T1y to T1o and the secondary transfer roll T2b.
Ed: Power supply circuit for fixing The power supply circuit for fixing Ed supplies power for heating the heater to the heating roll Fh of the fixing device F.

(Function of the control unit C of the printer body U1)
The control unit C of the printer main body U1 has a function of executing processing according to an input signal from the signal output element and outputting a control signal to each control element. That is, the control unit C has the following functions.
C1: Image Forming Control Unit The image forming control unit C1 controls the driving of each member of the printer U, the application timing of each voltage, and the like according to the image information input from the personal computer PC, thereby performing an image forming operation. Execute the job that is.
C2: Drive Source Control Unit The drive source control unit C2 controls the drive of the main motor M1 via the drive source drive circuit D1 to control the drive of the photoreceptors Py to Po and the like.

C3: Power Supply Circuit Control Unit The power supply circuit control unit C3 controls the power supply circuits Ea to Ed to control the voltage applied to each member and the power supplied to each member.
C4: Image Density Calculation Unit The image density calculation unit C4 calculates the density Ca of an image to be printed based on image information input from a personal computer. The image density calculation unit C4 according to the first exemplary embodiment calculates the ratio of the number of pixels P1 written by the exposure devices ROSy to ROSo with respect to the total number of pixels P2 corresponding to the entire area of the image. Calculate as Ca. That is, it is calculated by Ca = P1 / P2. In the first embodiment, the calculation of the image density Ca is performed for each of Y, M, C, K, and O colors.

C5: Low Density Threshold Storage Unit The low density threshold storage unit C5 stores a threshold value C0 for determining whether or not the image density is low. The low-density threshold storage unit C5 according to the first embodiment stores C0 = 2 [%] as an example of the threshold C0.
C6: Low Density Discriminating Unit The low density discriminating unit C6 discriminates whether or not the density of an image to be printed is low. The low density determination unit C6 according to the first exemplary embodiment determines that the image is a low density image when the image density Ca is equal to or lower than the low density threshold value C0. In the first embodiment, the low-density image is determined for each of Y to O colors.

C7: Storage unit for deterioration addition value Storage unit C7 for deterioration addition value is used when a low-density image is printed and the developer contained in the developing devices Gy to Go is deteriorated. The deterioration addition value Na is stored. In the first embodiment, Na = 1 is set as an example of the deterioration addition value.
C8: Storage means for deterioration subtraction value The storage means C8 for deterioration subtraction value is used when high-density image printing is performed and the deterioration of the developer contained in the developing devices Gy to Go is eliminated. The degradation subtraction value Nb is stored. In the first embodiment, Nb = 3 is set as an example of the subtraction value for deterioration.

C9: Storage means for subtraction value during consumption The storage means C9 for subtraction value during consumption stores a subtraction value Nc during consumption that is used when the developer is forcibly consumed. That is, the subtraction value Nc used when the toner band 1 described later is formed is stored. In the first embodiment, a plurality of subtraction values Nc are stored as the subtraction value Nc at the time of consumption based on the consumption amount of the developer corresponding to the width of the formed toner band 1.
C10: Accumulated Deterioration Value Counting Unit The accumulated degradation value counting unit C10 measures the degree of deterioration of the developer contained in the developing devices Gy to Go. The cumulative degradation value counting means C10 of the first embodiment uses the cumulative degradation value N1 to measure the degree of degradation. When the low-density image is printed, the degradation accumulation value counting unit C10 according to the first embodiment adds the addition value Na to the accumulation value N1. When a high-density image is printed, the subtraction value Nb is subtracted from the accumulated value N1. Further, when a consumption image is printed, a subtraction value Nc corresponding to the width of the toner band 1 is subtracted from the accumulated value N1. Note that the initial value and the minimum value of the cumulative value N1 are set to N1 = 0. In the first embodiment, the cumulative value is counted for each of the colors Y to O.

C11: Degradation threshold value storage means The degradation threshold value storage means C11 determines whether the degree of deterioration of the developer contained in the developing devices Gy to Go is such that the developer is forcibly discharged. The threshold value N2 for deterioration is stored. As an example, the deterioration threshold N2 of the first embodiment is set to N2 = 50. It should be noted that the deterioration threshold N2 is preferably set with a sufficient margin and margin as compared with a state in which development failure occurs due to developer deterioration.
C12: Deterioration determination means The deterioration determination means C12 determines whether or not a preset condition for deterioration of the developer is satisfied. The deterioration determining means of the first embodiment determines that the condition that the developer has deteriorated is satisfied when a low-density image is repeatedly printed. Specifically, when the low-density image is repeatedly printed and the accumulated deterioration value N1 becomes equal to or greater than the deterioration threshold value N2, it is determined that the condition that the developer has deteriorated is satisfied. In the first embodiment, the deterioration determination is performed for each of the colors Y to O.

C13: Image Width Acquisition Unit The image width acquisition unit C13 acquires the width of an image to be printed. That is, the length in the width direction intersecting the conveyance direction of the medium on which the image is recorded is acquired. The image width acquisition unit C13 according to the first exemplary embodiment acquires the width of an image to be printed from the image size information included in the image information received from the personal computer PC.
C14: Maximum Width Storage Unit The maximum width storage unit C14 stores the maximum image width that can be printed by the printer U. Note that the maximum printable image width is preset and stored.
C15: Width Determination Unit The width determination unit C15 determines whether the width of the image printed on the recording sheet S is smaller than the maximum printable image width. In the first embodiment, the image width is determined for the color determined to satisfy the condition that the developer has deteriorated.

FIG. 4 is an explanatory diagram of an example of an image for consumption of the developer according to the first exemplary embodiment.
C16: Bandwidth setting means Bandwidth setting means C16, which is an example of the developer consumption image size setting means, sets the size of the toner band 1 as an example of the developer consumption image. Set. The bandwidth setting unit C16 according to the first exemplary embodiment, when the width of the image printed on the recording sheet S is smaller than the width of the maximum printable image, the maximum printable width L1. The width L3 of the toner band 1 formed outside the width 2 of the image 2 to be printed is set based on the width L2 of the image 2. In Example 1, the toner band 1 is set so as to be formed on both sides of the image 2 in the width direction. In the band width setting unit C16 according to the first exemplary embodiment, the width L3 of each toner band 1 formed on both sides is a width excluding a preset gap between the image 2 and the toner band 1, that is, a so-called margin L4. The width L3 of the toner band 1 is set. That is, L3 = (L2-L1) / 2-L4 is set. In Example 1, the length L5 of the toner band 1 is set to the length L5 of the image to be printed.

C17: Band forming means A band forming means C17 as an example of a consumption image forming means is an exposure machine when the width L1 of an image to be printed is smaller than the width L2 of the maximum printable image. By controlling ROSy to ROSo, the toner band 1 is formed in the region 3 between the maximum printable image width L2 and the printed image width L1. The band forming means C17 of Example 1 forms a band-shaped image having a density of 100%, that is, a so-called band-shaped solid image, as the toner band 1.

(Explanation of flowchart of Example 1)
Next, a flow of control in the printer U according to the first embodiment will be described with reference to a flowchart, a so-called flowchart.

(Explanation of Flowchart of Developer Deterioration Measurement Process)
FIG. 5 is an explanatory diagram of a flowchart of the developer deterioration measurement process of the first embodiment.
5 is performed according to a program stored in the control unit C of the printer U. This process is executed in parallel with other various processes of the printer U.
The flowchart shown in FIG. 5 is started when the printer U is powered on.

In ST1 of FIG. 5, it is determined whether or not an image forming operation, so-called job, has been started. If yes (Y), proceed to ST2. If no (N), repeat ST1.
In ST2, the density Ca of the image to be printed is calculated. Then, the process proceeds to ST3.
In ST3, it is determined whether or not the density Ca of the image to be printed is equal to or lower than the low density threshold value C0. If yes (Y), proceed to ST4. If no (N), the process proceeds to ST5.
In ST4, the addition value Na is added to the accumulated deterioration value N1. That is, N1 = N1 + Na. Then, the process proceeds to ST6.
In ST5, the subtraction value Nb is subtracted from the accumulated deterioration value N1. That is, N1 = N1-Nb. Then, the process proceeds to ST6.
In ST6, it is determined whether or not the job is finished. If no (N), the process returns to ST2. If yes (Y), the process returns to ST1.

(Description of flowchart of toner band creation processing)
FIG. 6 is an explanatory diagram of a flowchart of toner band creation processing according to the first exemplary embodiment.
6 is performed according to a program stored in the control unit C of the printer U. This process is executed in parallel with other various processes of the printer U.
The flowchart shown in FIG. 6 is started when the printer U is turned on.

In ST11 of FIG. 6, it is determined whether or not the job is started. If yes (Y), proceed to ST12. If no (N), ST11 is repeated.
In ST12, it is determined whether or not the accumulated deterioration value N1 is equal to or greater than a deterioration threshold value N2. If yes (Y), the process proceeds to ST13. If no (N), the process proceeds to ST17.
In ST13, it is determined whether or not the width L1 of the image to be printed is smaller than the width L2 of the maximum image that can be printed by the printer U. If yes (Y), the process proceeds to ST14. If no (N), the process proceeds to ST17.

In ST14, the bandwidth L3 is set based on the width L1 of the image to be printed, the width L2 of the maximum image, and the like. Then, the process proceeds to ST15.
In ST15, a toner band 1 corresponding to the set bandwidth L3 is created. Then, the process proceeds to ST16.
In ST16, the subtraction value Nc at the time of consumption is subtracted from the accumulated deterioration value N1 in accordance with the width L3 of the toner band 1. That is, N1 = N1-Nc. Then, the process proceeds to ST17.
In ST17, it is determined whether or not the job is finished. If no (N), the process returns to ST12. If yes (Y), the process returns to ST11.

(Function of control processing of embodiment 1)
In the printer U according to the first embodiment having the above-described configuration, when many low-density images are printed when printing is performed, the deterioration accumulation value N1 increases. When the cumulative deterioration value N1 is equal to or greater than the deterioration threshold value N2, the toner band 1 is created. Accordingly, the developer in the developing devices Gy to Go is consumed as the toner band 1 is produced. When the developer in the developing units Gy to Go is consumed, a new developer is supplied from the toner cartridges Ky, Kc, Km, Kk, Ko according to the consumption. Therefore, in the developing devices Gy to Go, the deteriorated developer is consumed and a new developer is supplied, and the developer is replaced as a whole. Therefore, the occurrence of development failure due to the deterioration of the developer is reduced as compared with the case where the replacement of the developer is not performed.

  When an image having a low density is printed, the developer contained in the developing units Gy to Go circulates while being stirred inside the developing units Gy to Go with a small amount of consumption. If the developer is stirred for a long time without being consumed, the developer is likely to deteriorate. Therefore, there is a high risk of developing failure. In a configuration in which a toner band is formed in a non-image area between an image and the next image as in the configuration described in Patent Document 1, the developer is forcibly consumed by the toner band, and the deteriorated developer is removed. It is discharged outside the developing unit. However, in the configuration described in Patent Document 1, it is necessary to provide a certain distance between the image and the next image, including the width of the toner band and the margin between the previous and next images. Therefore, there is a limit to improving the number of printed images per unit time, so-called productivity. If the toner band is not formed, the interval between the image and the next image is reduced. If the toner band is formed, the interval can be increased. However, even in this configuration, when the interval is increased. Reduces productivity.

  On the other hand, in the printer U according to the first embodiment, when there is a width in which the toner band 1 can be formed, the toner band 1 is formed on the outer side in the width direction of the image 2 to be printed. Consumed developer is consumed. Therefore, the interval between the image 2 to be printed and the next image can be reduced to the limit. Therefore, productivity can be improved as compared with the conventional configuration.

  Further, in the printer U according to the first embodiment, the toner is added based on the accumulated deterioration value N1 that is added when the low-density image is printed and subtracted when the high-density image is printed. Band 1 is being created. Assuming that the toner band 1 is created when 50 low-density images are continuously performed, for example, after printing 40 low-density images, one high-density image is printed. In the case where printing of 40 low density images is performed thereafter, the toner band 1 may not be created indefinitely. On the other hand, in the printer U according to the first embodiment, the accumulated deterioration value N1 is used to measure the degree of deterioration. Accordingly, the accuracy of determination of the degree of deterioration is improved as compared with the case where determination is made only by the continuous number of printed sheets, and the toner band 1 is created at an appropriate time. Further, in the printer U of the first embodiment, when a high-density image is printed and more developer is consumed than in the case of a low density, and the replacement of the deteriorated developer proceeds, the accumulated deterioration value N1 Is subtracted. Therefore, unnecessary developer consumption is suppressed.

FIG. 7 is an explanatory diagram of an example of an image for consuming the developer according to the second embodiment, and corresponds to FIG. 4 according to the first embodiment.
FIG. 8 is an explanatory diagram of a main part of the developing device of Example 2.
Next, a second embodiment of the present invention will be described. In the description of the second embodiment, components corresponding to the components of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. To do.
The second embodiment is different from the first embodiment in the following points, but is configured in the same manner as the first embodiment in other points.

In FIG. 7, in the printer U of the second embodiment, unlike the first embodiment in which the image 2 is printed with the center in the width direction as a reference, the image 2 to be printed is printed with the front end that is one end in the width direction as a reference. The Therefore, in the printer U of the second embodiment, the toner band 1 is formed only on the rear side which is the other end, unlike the first embodiment formed on both sides in the width direction.
In FIG. 8, in the developing devices Gy to Go of Example 2, a developing roll 11 as an example of a developer holding member is disposed to face the photoreceptors Py to Po. A supply auger 12 as an example of a first conveying member is disposed at a position adjacent to the developing roll 11. The supply auger 12 has a rotating shaft 12a extending in the front-rear direction. A first transport blade 12b as an example of a first transport unit is supported on the rotary shaft 12a.
An admixing auger 13 as an example of a second transport member is disposed at a position opposite to the developing roll 11 with respect to the supply auger 12. Similar to the supply auger 12, the admix auger 13 also includes a rotation shaft 13a extending in the front-rear direction and a second transport blade 13b as an example of a second transport unit.

A partition wall 14 as an example of a partition portion is disposed between the supply auger 12 and the admix auger 13. The partition wall 14 extends in the front-rear direction, and passage portions 14 a and 14 b through which the developer can pass are formed at both front and rear ends.
In the second embodiment, the rotation direction is set so that the supply auger 12 conveys the developer from the front to the rear, and the admix auger 13 conveys the developer from the rear to the front.

(Operation of Example 2)
In the printer U of Example 2 having the above-described configuration, the toner band 1 is formed only on the rear side in the width direction. Therefore, as in the first embodiment, productivity can be improved as compared with the technique described in Patent Document 1. Further, when forming on both sides in the width direction, each toner band 1 needs to have a margin L4 with respect to the image 2. That is, two margins L4 are necessary. On the other hand, in Example 2, it is formed only on one side in the width direction, and only one margin L4 is required. Therefore, the width of the toner band 1 can be increased. Therefore, it is possible to increase the amount of developer that can be consumed at one time when the toner band 1 is formed.

  In the developing devices Gy to Go according to the second embodiment, the supply auger 12 conveys the developer from the front to the rear. Therefore, the rear side where the toner band 1 is formed is set on the downstream side with respect to the conveyance direction of the supply auger 12. If the toner band 1 is formed on the front side, the developer is consumed at a position upstream of the developer conveyed by the supply auger 12, and the developer is insufficient from the midstream portion where the image 2 is formed to the downstream portion. There is a fear. On the other hand, in Example 2, the toner band 1 is formed on the rear side corresponding to the downstream side in the conveyance direction of the supply auger 12, and the toner band 1 is formed with the developer after the image 2 is formed. The Therefore, the adverse effect of the toner band 1 on the image 2 is reduced.

(Example of change)
As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is performed within the range of the summary of this invention described in the claim. It is possible. Modification examples (H01) to (H09) of the present invention are exemplified below.
(H01) In the above-described embodiment, the printer U as an example of the image forming apparatus is illustrated. However, the present invention is not limited to this. For example, the printer U is configured by a copying machine, a FAX, or a multifunction machine having a plurality or all of these functions. It is also possible to do.
(H02) In the above-described embodiment, the configuration in which the developer of five colors is used as the printer U is illustrated. However, the present invention is not limited to this, and for example, a single-color image forming apparatus, four colors or less, or six colors or more The present invention can also be applied to a multicolor image forming apparatus.

(H03) In the above-described embodiments, the specific numerical values and parameters illustrated can be arbitrarily changed according to the design and specifications.
(H04) In the above-described embodiment, a configuration in which a solid image is used as the toner band 1 is illustrated, but the present invention is not limited to this. That is, an image having an arbitrary density can be used as the toner band 1. Further, for example, when the degree of deterioration is low, it is possible to create a toner band 1 with a low density, and when the degree of deterioration is high, it is possible to create a toner band 1 with a high density. That is, in a normal situation, a toner band 1 having a low density is created, and when the state where the width of the image 2 is wide and the toner band 1 cannot be formed continues and the degree of deterioration becomes high, the toner band 1 It is also possible to create a toner band 1 having a high density when it can be formed. That is, a configuration having a plurality of threshold values such as a threshold value for determining when the degree of deterioration is low and a threshold value for determining when the degree of deterioration is high, or a toner band in proportion to the degree of deterioration. It is also possible to change such that the density of 1 is changed.

(H05) In the above-described embodiment, the configuration in which the toner band 1 is created when the cumulative deterioration value N1 is equal to or greater than the deterioration threshold value N2, that is, when the deterioration has progressed to some extent has been illustrated. Not. For example, even when the deterioration has not progressed, when printing a low density image, it is possible to form the toner band 1 every time to make it difficult for the deterioration to progress.
(H06) In the above embodiment, the configuration in which the toner band 1 is formed outside the image 2 is exemplified, but the present invention is not limited to this. For example, the toner band 1 can be formed so as to overlap the image 2 in an area where the toner band 1 can be formed even inside the image 2. For example, when printing a mark image for cutting, that is, a so-called “register mark”, the toner band 1 can be formed in an area that is cut and discarded in an area outside the register mark. In this case, the density of the toner band 1 can be reduced in consideration of the visibility of the registration mark image.

(H07) In the above embodiment, the image density is used to determine the condition under which the developer has deteriorated, but the present invention is not limited to this. Any parameter related to developer degradation can be used. For example, the ratio between the developer replenishment amount from the toner cartridges Ky to Ko and the driving time of the motors of the developing units Gy to Go can be used as a parameter. That is, when the replenishment amount is small in spite of a long driving time of the motors of the developing devices Gy to Go, it can be determined that the developer is stirred for a long time without being consumed.
(H08) In the above-described embodiment, for example, when the situation in which the toner band 1 cannot be created continues, the image formation is temporarily interrupted, the toner band 1 is created, and the developer is forcibly consumed. It is also possible to configure. For example, a threshold value for determining whether or not image formation is temporarily interrupted is provided, and when the deterioration deterioration value N1 exceeds a threshold value for determining whether or not to temporarily stop image formation, the toner band 1 is created by temporarily interrupting image formation. Is also possible.

(H09) In the above-described embodiment, when the degree of deterioration is determined, the configuration in which the number of images whose image density is equal to or less than the threshold value C0 is exemplified. However, the present invention is not limited to this. For example, the number of pixels written by the exposure machines ROSy to ROSo, that is, the cumulative value of the so-called number of pixels, is counted, and the cumulative value of the number of media and the rotational speeds of the photoreceptors Py to Po becomes a preset value each time. It is also possible to determine the degree of deterioration by determining the average density during the period from the number of pixels.

1. Image for consumption of developer,
2 ... Images to be printed
C12: means for determining deterioration,
C15: means for determining the width,
C17: image forming means for consumption,
F: Fixing device,
Gy, Gm, Gc, Gk, Go ... developer,
L1: the width of the image to be printed,
L2: The maximum printable image width,
Py, Pm, Pc, Pk, Po ... image carrier,
ROSy, ROSm, ROSc, ROSK, ROSo ... exposure machine,
S ... medium
T1, B, T2 ... transfer device,
U: Image forming apparatus.

Claims (3)

An image carrier,
An exposure machine that forms a latent image on the surface of the image carrier;
A developing device for developing a latent image on the surface of the image carrier into a visible image;
A transfer device for transferring an image of the image carrier to a medium;
A fixing device for fixing the image transferred to the medium;
A width determining means for determining whether or not a width of an image printed on the medium is smaller than a preset maximum printable image width;
When the width of the image to be printed is smaller than the width of the maximum printable image, the exposure machine is controlled to control the width of the maximum printable image and the width of the image to be printed. A consumption image forming means for forming a developer consumption image in a region between
An image forming apparatus comprising: A deterioration determining means for determining whether or not a preset developer satisfies a deteriorated condition;
The consumption image forming means for forming an image for consumption of the developer when it is determined that the developer has deteriorated;
The image forming apparatus according to claim 1, further comprising: The deterioration determining means for determining that the developer has deteriorated when an image having a density lower than a preset image density is repeatedly printed;
The image forming apparatus according to claim 2, further comprising:

Images