JP2008111963A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the frequency of interrupting development due to replenishment of toner as compared with the conventional art. <P>SOLUTION: In an image forming apparatus, when the arithmetic result of the toner of an arithmetic section 33 shows the number of consuming dots D<SB>cons</SB>≥a predetermined value D<SB>lim</SB>, and when a paper amount P<SB>rem</SB>detected by a paper amount detector 61 is P<SB>rem</SB>>P<SB>cap</SB>1 (P<SB>cap</SB>1 is a predetermined reference value), a printing control section 31 controls a printing section 2 to interrupt printing and a toner replenishment control section 32 controls a toner replenishing device 5 to replenish the toner. On the other hand, when the paper amount P<SB>rem</SB>is P<SB>cap</SB>0<P<SB>rem</SB>≤P<SB>cap</SB>1 (P<SB>cap</SB>0 is a reference value less than P<SB>cap</SB>1), the toner replenishment control section 32 replenishes the toner after the completion of printing, and when the paper amount P<SB>rem</SB>is P<SB>rem</SB>=P<SB>cap</SB>0, printing is interrupted, a controller 3 makes a request to replenish paper and simultaneously the toner replenishment control section 32 performs a toner replenishing operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus capable of interrupting image formation according to the remaining amount of a developer and a recording medium.

Currently, various apparatuses have been proposed as image forming apparatuses that print out an image formed with a developer on a recording medium such as paper according to image data, such as a printer or a copier. The image forming apparatus includes a developer that can accommodate a developer therein and that develops an image with the developer. The image forming apparatus further includes a developer replenishment mechanism that replenishes the developer. There is something.
JP 2006-208990 A (August 10, 2006)

  However, in the conventional technology, for example, when the developer cannot be replenished by the replenishment mechanism during the developing operation of the developing device such as a rotary image forming apparatus, the developing operation is interrupted and the developer is replenished. It was.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of reducing the frequency with which a developing operation is interrupted by supplying a developer more than before.

  The image forming apparatus according to claim 1 is an image forming apparatus that forms an image on a recording medium in accordance with image data, a developing unit that develops an image with a developer accommodated therein, and a non-development of the developing unit A developer replenishment unit capable of replenishing the developer to the developer sometimes, a developer amount detector for detecting the amount of developer in the developer, a recording medium amount detector for detecting the amount of the recording medium, Based on the detection results of the developer amount detector and the recording medium amount detector, when the recording medium amount becomes a predetermined first value or less during the developing operation by the developer, or the developer amount is a predetermined value. And when the recording medium amount exceeds a second value greater than the first value, the development is interrupted, while the developer amount is not more than the predetermined value and the recording medium amount. When exceeds the first value and falls below the second value , And a developing control unit capable of controlling the developer unit so as to continue the development.

  In the image forming apparatus, the developer is replenished by the developer replenishing unit when not developing. Here, the image forming apparatus includes the development control unit or the like, so that the recording medium amount is equal to or less than a predetermined first value during the developing operation by the developing device, or the developer amount is a predetermined amount. When the recording medium amount is less than the value and exceeds the second value larger than the first value, the developer can be replenished by interrupting the development. On the other hand, the development control unit or the like causes the image forming apparatus to have the developer amount not more than the predetermined value and the recording medium amount exceeding the first value and not more than the second value. In some cases, development is not interrupted.

  That is, the image forming apparatus can interrupt and continue the developing operation based on both the recording medium amount and the developer amount. Therefore, the frequency of interrupting development can be kept lower than when the developing operation is interrupted based solely on the developer amount. As a result, the time required for the image forming operation can be shortened, and the image can be provided to the user more quickly.

  According to a second aspect of the present invention, the developer replenishing section determines that the developer amount is equal to or less than the predetermined value and the recording medium amount from the detection results of the developer amount detector and the recording medium amount detector. When the value exceeds the first value and is equal to or less than the second value, the developer may be replenished after the development by the developing device is completed.

  Thus, the image forming apparatus can replenish the developer without interrupting the developing operation.

  The image forming apparatus includes the development control unit and the like, so that the development operation can be interrupted and continued based on both the recording medium amount and the developer amount. Therefore, the frequency of interrupting development can be kept lower than when the developing operation is interrupted based solely on the developer amount. As a result, the time required for the image forming operation can be shortened, and the image can be provided to the user more quickly.

[1] Configuration of Multifunction Device 1 The present invention will be specifically described below by taking the multifunction device 1 as an embodiment. In addition, this invention is not limited to the following embodiment.

  1 and 2 are views showing a main configuration of a multifunction machine 1 according to this embodiment. FIG. 1 is a block diagram and FIG. 2 is a front view.

  As shown in FIG. 1, the multifunction device 1 includes a printing unit 2 that forms an image according to image data on a sheet, a control device 3 that controls each unit of the multifunction device 1, and a developing device 40 in the printing unit 2 (see FIG. 1). 2) a toner replenishing device 5 for replenishing toner, a paper amount detector 61 for detecting the amount of paper in the following paper cassette 25, a toner concentration detector 62 for detecting the toner concentration in the developing unit 40, and various information. A display unit 71 that can be presented to the user, an operation panel 72 that can accept input from the user, and the like. Details of the printing unit 2 and the toner replenishing device 5 will be described later with reference to FIG.

  In response to an instruction received from the user via the operation panel 72 or the like, the control device 3 sends and receives data signals and control signals to and from each unit of the multifunction device 1 and controls image processing operations and data transmission operations. Control. Specifically, the control device 3 can be configured by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU can perform various calculations and execute programs. The ROM stores a program related to control performed by the CPU, a program related to the operation of each unit in the multi-function peripheral 1, and the like. In addition to functioning as a work area for the CPU, the RAM has an area for holding user input contents and the like.

  In particular, the control device 3 includes a print control unit 31, a toner supply control unit 32, and a calculation unit 33 (FIG. 1). The print control unit 31 can control the printing unit 2 to execute printing or the like. The toner replenishment control unit 32 can control the toner replenishing device 5 to replenish toner based on the detection result of the toner density detector 62 and the like.

The calculation unit 33 performs calculation based on outputs from various detectors and the like, and in particular, can calculate the toner amount in the developing device 4 (developer tank 41 described later in detail). Specifically, the calculation unit 33 can acquire the number of dots from the image data. From this number of dots, the number of consumed dots D _cons from the toner full state or the last replenishment can be calculated. The computing unit 33 can compare the consumed dot number D _cons with the upper limit value D _lim of the dot number defined in advance. The toner replenishment control unit 32 controls the toner replenishing device 5 to replenish toner when the number of consumed dots D _cons reaches the upper limit value D _lim and a predetermined condition is satisfied.

Note that the upper limit value D _{lim of the} number of consumed dots is not particularly limited, and can be changed as appropriate. However, as will be described in detail later, the control device 3 of the present embodiment may cause the printing unit 2 to continue printing even when the number of consumed dots D _cons reaches the upper limit value D _lim . Therefore, the upper limit value D _lim is preferably set to a value that allows printing to be continued to some extent even when the number of consumed dots D _cons reaches the upper limit value D _lim .

Further, the computing unit 33 compares a sheet amount _Prem in a sheet cassette 25 described later with two predetermined values (first value and second value) from the detection result of the sheet amount detector 61. be able to. Based on the comparison result, the control device 3 can cause each unit of the multifunction device 1 to execute an operation for requesting the user to supply paper. The first value can be appropriately changed according to the user's request, the configuration of the multi-function device 1 and the like as long as the remaining amount of paper is not less than 0 and less than the full amount. Further, the second value can be a value larger than the first value and less than the full amount.

In this embodiment, in particular, the paper amount when the paper cassette 25 is full is P _ful , the first value is P _cap 0, the second value is P _cap 1, and P _cap 0 is the remaining paper amount. _Assume that the quantity is 0, and P _cap 1 is a quarter quantity of P _ful .

  Details of the function of the control device 3 will be described in the following [2] column.

  The paper amount detector 61 may be any device that can detect the amount of paper, and a known technique can be used.

The toner concentration detector 62 may be any device that can detect the toner concentration in the developer in the developing device 41 described below, and a known technique can be used. Examples of such a technique include a technique for detecting the toner density from the light transmittance. Here, the detection result of the toner concentration detector 62 is expressed as toner concentration T _meas .

  The display unit 71 displays various screens under the control of the control device 3 by a display device such as a liquid crystal display device. The operation panel 72 includes a touch panel, hard keys, and the like.

  The printing unit 2 includes a developing unit 4, an intermediate transfer unit 21, a secondary transfer roller 22, a paper feed cassette 25, a paper feed cassette 25, a paper feed unit 23, a transport unit 24, a fixing unit 26, and the like.

  The developing unit 4 can form a toner image according to the image data. Details of the developing unit 4 will be described later.

  The intermediate transfer unit 21 includes an intermediate transfer belt 21a and an intermediate transfer roller 21b. The intermediate transfer belt 21a is an annular flat belt and is conveyed in the direction indicated by the arrow B. The intermediate transfer roller 21b primarily transfers the toner image formed by the developing unit 4 onto the intermediate transfer belt 21a.

  The paper feed cassette 25 can store paper, and this paper is taken out by the paper feed unit 23 during printing. The transport unit 24 can transport the taken paper in the direction indicated by the arrow A in the drawing. The paper feeding unit 23, the secondary transfer roller 22, and the fixing unit 26 are arranged in this order along the conveyance direction of the conveyance unit 24. The transport unit 24 transports the taken paper, and the toner image primarily transferred to the intermediate transfer belt 21 a is secondarily transferred onto the paper by the secondary transfer roller 22. The fixing unit 26 fixes the toner image on the paper after the secondary transfer by thermocompression bonding. The sheet after fixing is finally discharged to the outside of the multifunction machine 1 by the transport unit 24.

  As shown in FIG. 2, the developing unit 4 includes a photosensitive drum 10 that is rotatably held in the direction of arrow C, and along the rotating direction of the photosensitive drum 10, the charging unit 11, the laser unit 12, and the developing unit. Unit 40, cleaning device 13 and the like. The charging unit 11 can uniformly charge the photosensitive drum 10, and an electrostatic latent image is drawn when the laser unit 12 irradiates light on the surface of the charged photosensitive drum 10. Then, the developing unit 40 conveys the toner to the electrostatic latent image on the surface of the photosensitive drum 10, whereby a toner image in which the electrostatic latent image is visualized is formed. The intermediate transfer roller 21b primarily transfers the toner image onto the intermediate transfer belt 21b downstream of the developing device 40 in the rotation direction C of the photosensitive drum 10. The cleaning device 13 can remove toner remaining on the surface of the photosensitive drum 10 after the primary transfer further downstream.

  The developing unit 40 employs a rotary system in this embodiment. The developing unit 40 includes four developing devices 41 around one rotation axis parallel to the rotation axis of the photosensitive drum 10. Each developing device 41 includes a developer tank and a developing roller. The developer tank contains four color developers of Y (yellow), M (magenta), C (cyan), and K (black). In the present embodiment, the developing device 41 uses a two-component developer containing toner and carrier. The developing roller can develop the image data as a toner image by conveying the toner onto the photosensitive drum 10. The developing unit 40 can sequentially face the photosensitive drum 10 by rotating the developing device 41 around the rotation axis. A position where the developing device 41 faces the photosensitive drum 10, that is, a position where the toner can be conveyed to the photosensitive drum 10 is referred to as a developing position.

  The toner supply device 5 includes a nozzle 5a, a drive mechanism 5b, and a toner tank 5c. At least four nozzles 5a and four toner tanks 5c are provided. Each toner tank 5b contains the above four colors of toner, and the nozzle 5a replenishes the corresponding color developing device 41 from the toner tank 5b. The drive mechanism 5b can be arranged at the retreat position i and the replenishment position ii by moving the nozzle 5a. The retreat position i is a position when the toner is not replenished, and the replenishment position ii is a position where the nozzle 5a is inserted into the developer tank of the developing device 41 and is a position where the toner can be replenished. In FIG. 2, the replenishing device 5 replenishes toner to the developing device 41 in the developing position, but the present invention is not limited to this.

  The structure of the developing device 41 for supplying toner will be described in more detail with reference to FIG. FIG. 3 is a perspective view showing a configuration of a main part of the developing device 41. The developing device 41 includes a developing device main body 42. Each developing device main body 42 is configured such that a cross section in a plane perpendicular to the rotation axis of the developing device 41 has a substantially fan shape. The developing device 41 is disposed in the developing unit 40 with the center of the fan shape directed toward the rotating shaft. An elastic member 43 made of a material having elasticity such as urethane is provided in a region corresponding to the arc. The elastic member 43 is provided with a cut 44. In the developing device 41, the nozzle 5a enters the developing device main body 42 through the notch 44 at the replenishment position ii so that toner can be replenished to the developer tank. Further, a valve or the like is provided inside the developing device main body 41 of the notch 44. When the nozzle 5a is in the retracted position i, the cut 44 is closed by the elasticity of the elastic member 43, and the developer is prevented from flowing out of the developing device 40 by this valve.

[2] Processing Operation at the Time of Printing (2-1) Overview of Processing Operation Hereinafter, an overview of the processing operation at the time of printing will be described with reference to the flowchart of FIG.

When receiving the print instruction, the multifunction device 1 starts a printing operation under the control of the control device 2 (S1). When the number of consumed dots D _cons reaches the upper limit value D _lim , the control device 3 turns on the toner replenishment flag (Yes in S2 →→ S4 → S5). That is, as described above in the section [2], the calculation unit 33 obtains the number of dots obtained from the image data, obtains the number of consumed dots D _cons therefrom, and obtains the number of consumed dots D _cons and the upper limit value D _lim . Compare Then, the control device 2 turns on the toner supply flag in accordance with the comparison result.

Further, under the control of the control device 3, processing such as toner replenishment is performed according to the paper amount _Prem obtained from the detection result of the paper amount detector 61 (S6). The control device 3 continues to monitor the toner amount and the paper amount until the printing is completed (No in S7 → S2).

  If the toner replenishment flag is ON after the printing is completed, a toner replenishment operation is performed (Yes in S7 → Yes in S8 → S9). When the toner supply operation is finished, the toner supply flag is turned off (S10), and the series of operations is finished. If the toner flag is OFF (No in S8), the toner supply is not performed and the series of operations is terminated.

(2-2) Processing according to the paper amount _Prem (S6)
Step S6 will be described in more detail based on the flowchart of FIG.

If the paper amount _Prem is larger than the second reference value P _cap 1 (Yes in S21), if the toner flag is ON, printing is interrupted and toner supply operation is performed (Yes in S22 → S23 → S24). . After toner supply, the toner supply flag is turned off and printing is resumed (S25 → S26 → S7 in FIG. 4). On the other hand, if the paper amount _Prem is greater than the second reference value P _cap 1 and the toner flag is OFF, toner replenishment is not performed and printing is continued (Yes in S21 → No in S22 → S7 in FIG. 4). ).

If the paper amount _Prem is equal to or smaller than the second reference value P _cap 1 and greater than the first reference value P _cap 0, the toner is not replenished and printing is continued (No in S21 → Yes in S27 → S7 in FIG. 4). .

On the other hand, if the paper amount _Prem is equal to or _smaller than the first reference value P _cap 0, the printing is interrupted and the printing is resumed after the paper and the toner are replenished (No in S27 → S28 →→ S26 → S7 in FIG. 4). .

(2-3) Paper and toner supply (S29)
Step S29 will be described in more detail based on the flowchart of FIG. As shown in FIG. 6, after the printing is interrupted, a paper supply request is made to prompt the user to supply paper (S31). Specifically, a message such as “no paper” is displayed on the display unit 71. If the toner flag is ON, the toner supply operation is performed to turn the toner supply flag OFF (Yes in S32 → S33 → S34). The paper supply request is continued until the paper is supplied, that is, until the paper amount _Prem is greater than 0 (No in S35 to S31). When the paper is supplied, the paper supply request is terminated and printing is resumed (Yes in S35 → S26 in FIG. 5). If the toner supply flag is OFF in step S32, the toner supply operation is not performed (No in S32 to S35).

(2-4) Toner replenishing operation (S9, S24, S33)
The toner supply operation in steps S9, S24, and S33 will be described with reference to the flowchart of FIG. As described above, when various conditions for starting toner supply are satisfied, the toner supply control unit 32 controls the toner supply device 5 to execute toner supply (S41). The control device 3 monitors the detection value of the toner concentration detector 62 and continues the toner supply until the toner concentration T _meas reaches the predetermined value T _ful (No in S42 → S41). When the toner density T _means reaches the predetermined value _Tful , the toner supply control unit 32 controls the toner supply device 5 to stop the toner supply (Yes in S42 → S43), and the toner supply operation ends.

As described in (2-2) above, in this embodiment, the print control unit 31 interrupts printing according to the paper amount _Prem , and the toner replenishment control unit 32 utilizes the interruption to supply the toner replenishing device 5. Toner can be replenished. Therefore, the multifunction device 1 does not interrupt printing just for toner replenishment, and the number of times printing is interrupted is reduced.

[3] Other Forms In the embodiments in the above [1] and [2] columns, development of image data and transfer / fixing onto paper are collectively referred to as “printing operation”. The print control unit 31 stops the printing operation when the toner is replenished. However, the present invention is not limited to this. At the time of toner replenishment, the developing device 41 only needs to be stopped to the extent that toner can be replenished. For example, processing (primary transfer, secondary transfer, fixing, etc.) that does not involve rotational movement of the developing device 41 is executed. It may be like this.

  The control device 3 capable of executing the operations shown in FIGS. 4 to 7 can be suitably used for an image forming apparatus in which it is difficult to simultaneously execute the developing operation and the developer supply operation. The developing unit 40 and the toner replenishing device 5 of this embodiment are merely examples of such a mechanism. That is, various specific configurations in the present embodiment, that is, a point using four color toners, a point using a two-component developer, or a point adopting a rotary developing method can be changed as appropriate.

The toner replenishment flag setting operation based on the number of consumed dots D _cons in the above embodiment can be replaced with the following operation. That is, to convert the full or when the toner amount after the most recent toner replenishing the number of dots to obtain the remaining amount of toner T _dev subtracts the consumed number of dots D _cons from the dot number, the remaining amount of toner T _dev is predetermined toner The operation is to turn on the toner replenishment flag if the replenishment level T _add or lower.

In the above embodiment, the condition that the toner supply flag is turned on is that the consumed dot number D _cons reaches the upper limit value D _lim of the dot number. However, the consumed dot number D _cons is merely an example of a parameter that reflects the amount of toner in the developing device. In other words, any parameter may be used as long as the amount of toner in the developing device can be grasped and the necessity of toner replenishment can be determined based on the amount. For example, the control device 3 may turn on the toner replenishment flag based on the detection result of the toner concentration by an optical sensor or the like.

In the above embodiment, the reference value of the toner amount in the developing device, which is a criterion for determining whether or not toner replenishment is necessary, is one upper limit value D _lim . However, the present invention is not limited to this, and a plurality of reference values may be provided for the amount of developer in the developing device. Here, it is assumed that the first reference value and the second reference value are set in order from the largest. At this time, when the amount of developer in the developing device becomes equal to or less than the first reference value, the control device 3 can prevent the developer from being replenished until printing is interrupted based on the amount of paper or until printing is completed. . Further, the control device 3 may be configured such that when the amount of developer in the developing device becomes equal to or less than the second reference value, printing is interrupted and developer replenishment is executed regardless of the amount of paper. According to such a configuration, development is performed when it takes a long time to complete printing or to interrupt printing due to shortage of paper after the amount of developer has decreased, such as a print job that requires a large amount of developer per sheet. The toner can be replenished before the image quality is deteriorated due to the shortage of the agent.

Specifically, in the above embodiment, the upper limit value D _lim (here a D _lim 1) can be set D _lim 1 greater than D _lim 2 to another. In this case, when the number of consumed dots D _cons is not less than D _lim 1 and less than D _lim 2, the control device 3 turns on the toner replenishment flag as described in section [2] above. After that, when the printing is completed without any interruption due to the decrease in the paper amount _{Prem and} the number of consumed dots D _cons becomes D _lim 2 or more, the control device 3 relates to the paper amount _Prem . Printing can be interrupted and toner can be replenished.

  In addition, it is needless to say that the technical scope of the present invention also includes techniques in which various modifications are made within the range in which the object of the present invention can be achieved.

1 is a block diagram showing a main configuration of a multifunction machine 1 according to an embodiment of the present invention. FIG. 2 is a front view illustrating a configuration of a main part of the multifunction machine 1. FIG. 3 is a perspective view illustrating a configuration of a main part of a developing device 41 in the multifunction machine 1. 6 is a flowchart showing the operation of the multifunction device 1. The flowchart which shows the detail of process step S6 shown in FIG. The flowchart which shows the detail of process step S29 shown in FIG. 7 is a flowchart showing details of the toner supply operation (S9, S24, S33) shown in FIGS.

Explanation of symbols

1 MFP (image forming device)
2 Printing unit 3 Control device 31 Printing control unit (development control unit)
32 Toner replenishment control unit 33 Calculation unit (developer amount detector)
4 Development unit 5 Toner supply device (developer supply unit)
61 Paper amount detector (Recording medium detector)
62 Toner concentration detector

Claims (2)

An image forming apparatus that forms an image on a recording medium according to image data,
A developing device for developing an image with a developer housed therein;
A developer replenishment section capable of replenishing the developer to the developer when the developer is not developed;
A developer amount detector for detecting the developer amount in the developer;
A recording medium amount detector for detecting the amount of the recording medium;
Based on the detection results of the developer amount detector and the recording medium amount detector, when the recording medium amount becomes a predetermined first value or less during the developing operation by the developer, or the developer amount is a predetermined value. And when the recording medium amount exceeds a second value greater than the first value, the development is interrupted, while the developer amount is not more than the predetermined value and the recording medium amount. Is greater than the first value and less than or equal to the second value, a development control unit capable of controlling the developer so as to continue development,
An image forming apparatus comprising:   From the detection results of the developer amount detector and the recording medium amount detector, the developer replenishing unit determines that the developer amount is equal to or less than the predetermined value and the recording medium amount exceeds the first value and The image forming apparatus according to claim 1, wherein the developer is replenished after the development by the developing device is finished when the value becomes equal to or less than two.

Images