JP2008039967A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that in the case a developing means is stopped in an image non-formation area in order to reduce fatigue/deterioration of developer, etc., frictional resistance between a cleaning blade and an image carrier increases, and cleaning failure, early deterioration of the cleaning blade, occurrence of abnormal sound, etc. are caused. <P>SOLUTION: When the specific image non-formation area is equal to or greater than a predetermined value, a rotating body that applies a lubricant to the image carrier is rotated at a speed lower than that in an image formation area. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus.

  In an electrophotographic image forming apparatus, an electrostatic latent image is formed on a photosensitive member, the electrostatic latent image is developed with toner, the toner image is transferred to a recording material, and the transferred toner image is heated and fixed. By doing so, an image is formed on the recording material.

  In the developing means where the development is performed, the developer is stirred and transported, resulting in continuous stress being applied to the developer. There is a problem of doing. Further, the operation member in the developing means is also deteriorated by a long-term operation.

Patent Document 1 proposes to detect the presence or absence of an image and to drive and control the developing unit based on the detection result for the purpose of reducing such fatigue and deterioration. The method of Patent Document 1 shortens the operating time of the developing means by stopping the developing means when there is no image, and reduces fatigue and deterioration of the developer and the like.
JP-A-5-134529

  In an electrophotographic image forming apparatus, a cleaning blade is generally used for cleaning an image carrier such as a photosensitive member or an intermediate transfer member. The cleaning blade wipes the surface of the image carrier by bringing the edge of the rubber blade into contact with the surface of the image carrier, but it is necessary that a lubricant be interposed between the cleaning blade and the image carrier. Otherwise, the frictional resistance becomes high and the cleaning blade does not slide smoothly on the surface of the image bearing, causing problems such as poor cleaning, early wear of the cleaning blade, and abnormal noise.

  In addition to forming an image, the toner functions as a lubricant that reduces the frictional resistance between the cleaning blade and the image carrier. However, as described above, when the developing means is stopped while operating the image carrier, the supply of toner to the surface of the image carrier is stopped, so that the toner on the image carrier is insufficient, and the cleaning blade However, the image carrier does not slide smoothly, and the driving torque of the image carrier rapidly increases or the cleaning blade deteriorates quickly.

  An object of the present invention is to solve the above-described problems that occur in control for preventing deterioration of a developer or the like.

The object is achieved by the following invention.
1.
In an image forming apparatus having an image forming unit that includes a developing unit having an image carrier and a developing sleeve, and continuously forms a toner image on the image carrier.
And a control unit that controls the developing sleeve. The control unit does not form a toner image by the image forming unit, and at least part of a predetermined non-image forming region in which the image carrier moves. An image forming apparatus, wherein the developing sleeve is controlled to rotate at a lower speed than in the forming region.
2.
In an image forming apparatus having an image carrier, an image forming unit that continuously forms a toner image on the image carrier, and a rotating body that applies a lubricant on the image carrier.
And a control unit that controls the rotating body. The control unit does not form a toner image by the image forming unit, and at least part of a predetermined non-image forming area in which the image carrier moves. An image forming apparatus that performs control to rotate the rotating body at a lower speed than in a forming area.
3.
The predetermined non-image forming area is an area in which the image carrier is operated without performing image formation by the image forming means in order to operate an operation unit other than the image forming means. 3. The image forming apparatus according to 1 or 2 above.
4).
The control unit stops the rotating body at the head of the predetermined non-image forming area, and rotates the rotating body at the low speed when a predetermined period elapses. The image forming apparatus described in 1.

  According to the present invention, since the lubricant is applied onto the image carrier even in the non-image forming area, the friction resistance between the cleaning blade and the image carrier increases due to the stop of the developing means in the non-image forming area. This eliminates an increase in driving torque of the image carrier, poor cleaning, and early deterioration of the cleaning blade due to an increase in frictional resistance.

  The present invention will be described below with reference to illustrated embodiments, but the present invention is not limited to these embodiments.

  FIG. 1 is a diagram showing an overall configuration of an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus main body A is a digital copying machine that forms an image by a known electrophotographic technique. The image forming apparatus main body A is provided with an automatic document feeder 1 at the top, and a post-processing apparatus B is connected thereto.

  The image forming apparatus main body A includes an automatic document feeder 1, a reading unit 2, an image forming unit 4, a fixing unit 5, a reverse sheet discharging unit 6, a refeed unit 7, a sheet conveying unit 8, a sheet feeding unit 9, and an operation display. It consists of part E and the like.

  The automatic document feeder 1 sends the documents D placed on the document table 10 to the document transport path 11 one by one and discharges them to the document discharge table 12. The image surface of the document D being conveyed is read by the reading unit 2 at the document reading position 13. When scanning images on both sides of the document D, the document D that has been scanned on the first surface is reversed by the reversing means 14 and sent again to the document transport path 11 to read the second surface, and the document is discharged. The paper is discharged onto the paper board 12.

  The reading unit 2 includes a light source 21, a first mirror unit 22, a second mirror unit 23, an imaging lens 24, a CCD 25, and the like. The original image information, which is optical information, is converted into electrical information. The converted document image information is subjected to processing such as A / D conversion, shading correction, and compression, and is stored in a memory.

  The exposure means 42 is a scanning optical system composed of a laser light source, a cylindrical lens, an Fθ lens, a mirror, a polygon, etc., and an image carrier using a laser beam that changes in accordance with image information read from the memory. The surface of the photosensitive member 40 is scanned to form a latent image on the surface of the photosensitive member 40.

  The image forming unit 4 develops the latent image formed on the surface of the photoreceptor 40 by the charging unit 41 and the exposure unit 42 with the developing unit 43 to visualize it as a toner image. The toner image is transferred to the paper P sent out by the registration roller 81 by the transfer / separation means 44. After the toner image has been transferred, the surface of the photosensitive member is subjected to the removal of residual toner by the cleaning unit 46 and is charged by the charging unit 41 to be used for the next latent image formation.

  The fixing unit 5 fixes the toner image on the paper P by heating and pressurizing the paper P carrying the toner image by the heat roller 51 and the pressure roller 52 that are arranged to face each other.

  The paper P on which image fixing has been completed is sent to the post-processing apparatus B by the paper discharge roller 55.

  When the paper P is reversed and discharged, the paper P is guided downward by the paper discharge guide 57, the rear end of the paper P is sandwiched between the reverse rollers 61 of the reversing means, and the paper P is reversed to the discharge rollers 55. Send it out.

  When image formation is performed on both sides of the paper P, the paper P is sent to the paper refeeding means 7 by the paper discharge guide 57 and a plurality of rollers, and the paper P is reversed by the reversing roller 71 of the paper refeeding means 7. The paper is again sent to the paper conveying means 8.

  The paper transport unit 8 transports the paper P sent out from the paper feed unit 9 through a paper transport path including a plurality of rollers and a guide member, and abuts the leading end of the paper P against the registration roller 81. Then, the toner image is sent out toward the photoreceptor 40 in order to receive the toner image.

  The sheet feeding unit 9 includes a first sheet feeding unit 91 having a small capacity tray, a second sheet feeding unit 92 having a large capacity tray, and a third sheet feeding unit 93. In these first to third paper feeding units, paper P of different sizes may be placed, or paper P of different paper quality may be placed.

  Each of the paper feeding units sends the paper P placed on each tray to the paper transport unit 8 one by one. The second paper feed unit 92 and the third paper feed unit 93 are provided with upper surface detection means for detecting the upper surface position of the stacked paper, and based on the upper surface detection signal from the detection means, the paper P The bottom of the tray that is loaded is raised and lowered.

  The operation display unit E is a touch panel provided on the upper surface of the main body of the image forming apparatus main body A. The operation display unit E has both display and input functions. The post-processing mode is selected by an operator setting operation.

  As shown in the figure, the post-processing apparatus B includes a first transport unit 100, a second transport unit 200, a paper stacking unit 300, a binding unit 500, a third transport unit 600, a paper discharge tray 700, a transport path switching unit G, and the like. Consists of

  In the post-processing apparatus B, the paper P is collected by the paper stacking means 300, and the paper P is bound by the binding means, for example, using a binding tape. The bundle of bound sheets P is discharged to the discharge tray 700 by the third transport unit 600. Reference numeral 800 denotes a half-folding unit that folds the central portion of the paper P with a fold as the fold, and the folded paper P is stacked on the paper stacking unit 300.

  FIG. 2 is a diagram showing the configuration of the image forming unit 4 in the image forming apparatus shown in FIG.

  The image forming unit 4 includes a photoconductor 40 as an image carrier, and an image forming unit is disposed around the photoconductor 40. The image forming unit includes a charging unit 41, an exposure unit 42, and a developing unit 43. In addition to the image forming unit, a transfer / separating unit 44 and a cleaning unit 46 are disposed around the photoreceptor 40.

  The photosensitive member 40 is a drum-shaped OPC photosensitive member, but a well-known one such as an aSi photosensitive member can be scattered, and a belt-shaped photosensitive member can also be used.

  The charging unit 41 includes a scorotron discharger, and a well-known device such as a roller charging device or a brush charging device can be used.

  The exposure means 42 is an exposure apparatus having a scanning optical system having a laser diode as a light source and having a polygon mirror and a lens. Can do.

  The developing means 43 is a developing means using a two-component developer mainly composed of toner and carrier, but may be a developing means using a one-component developer.

  The developing means 43 includes a developing sleeve 43a, a regulating member 43b for regulating the amount of the developer conveyed on the developing sleeve 43a, a conveying member 43c for supplying the developer to the developing sleeve 43a, and two for agitating and conveying the developer. The stirring / conveying screw 43d is provided.

  The transfer / separation means 44 includes two corotrons, but other transfer devices such as a transfer roller can also be used.

  The cleaning means 46 has a cleaning blade 46a, and the cleaning blade 46a removes the toner remaining on the photoreceptor 40 after transferring the photoreceptor 40 from the surface.

  In image formation, the photoreceptor 40 rotates clockwise as indicated by an arrow, and a toner image is formed on the photoreceptor 40 by charging, exposure, and development. The formed toner image is transferred onto the recording material P by the transfer / separation means 44, and the transferred toner image is fixed by the fixing device 5.

  FIG. 3 is a block diagram of a control system of the image forming apparatus according to the embodiment of the present invention.

  The control means 100 controls the entire apparatus to perform image formation, and performs drive control of a rotating body that applies a lubricant described below to the surface of the image carrier.

  101 is an exposure control unit for driving the exposure means 42 in FIG. 2, 102 is a motor as a photosensitive member driving means for rotationally driving the photosensitive member 40 in FIG. 2, and 103 is a driving means for driving the developing means 43 in FIG. The motor drives the developing sleeve 43a, the conveying member 43C, and the stirring / conveying screw 43d.

  The control of the control means 100 will be described with reference to the sequence chart shown in FIG.

  FIG. 4A shows a case where continuous image formation is performed by forming equal non-image formation areas between image areas over the entire image formation process, and FIG. 4B shows an image formation process in the insertion printing mode. That is, the case where a long non-image forming area is formed in the image forming process is shown.

  In FIG. 4A, R1, R2,... Rn are image forming areas of n images, and non-image forming areas NR1, NR2,. It is formed.

  The exposure control unit 101 outputs the image area signals S1, S2,... Sn, and drives the exposure means 42 to expose the photoreceptor 40.

  Prior to the image area signal, the control unit 100 drives the motors 102 and 103 to rotate the photosensitive member 40 at a constant speed V1 during the entire period of the image forming process, and the developing sleeve 43a of the developing unit 43 at a constant speed V2. Rotate.

  The developing sleeve 43a as a rotator that applies toner as a lubricant to the photoreceptor 40 rotates at a constant rotational speed V2 throughout the entire image forming process, and responds to the electrostatic latent image in the image forming regions R1, R2 to Rn. The toner adheres to the photoreceptor 40, and a small amount of toner adheres to the surface of the photoreceptor 40 in the non-image forming regions NR1 to NRn-1. As a result, the frictional resistance between the cleaning blade 46a and the photoreceptor 40 is properly maintained, and good cleaning is performed.

  In the image forming process shown in FIG. 4B in the insertion printing mode, image formation is performed as follows.

  In the continuous image formation in which the image forming regions R1, R2... And the non-image forming regions NR1, NR2... Are alternately arranged, the blank paper P is supplied from the second paper feeding unit 92 and the image forming unit 4 An image is formed on the paper P, and the insertion printing is inserted during the continuous image forming process. In the insertion printing, the sheet P on which an image is formed in advance is fed from the third sheet feeding unit, and the sheet P is transferred from the image forming apparatus to the post-processing apparatus B without image formation in the image forming unit 4. Sent. Accordingly, in the insertion printing, the non-image forming area NRk is formed between the image forming areas. Naturally, the length of the non-image forming NRk is longer than the normal non-image forming regions NR1, NR2,... NRn regularly formed in the continuous image forming process.

  In the non-image forming area NRk, the photoreceptor 4 is driven to rotate at a constant speed V1, but the image area signal S is not output. At the time point t1 when the leading portion of the non-image forming area NRk of the photoreceptor 40 reaches the developing unit 43, the motor 103 is stopped.

  After the stop, at a time point t2 after a predetermined time T0 has elapsed, the control unit 100 drives the motor 103 to rotate at a low speed to rotate the developing sleeve 43a at a speed V3 lower than the speed V2. At a time point t3 that is slightly earlier than the development means arrival time t4 of the non-image forming area NRk in the development means 43 by insertion printing, the control means 100 drives the motor 103 to rotate at a normal speed, and the developing sleeve 43a at a normal speed V2. Rotate.

  The rotational speed V3 of the developing sleeve 43a in the non-image forming region NRk is set to a value that does not cause the developer to be fatigued and that the toner as a lubricant is applied to the surface of the photoreceptor 40. The predetermined time T0 for stopping the developing sleeve 43a is set to a value such that the increase in the frictional resistance between the cleaning blade 46a and the photosensitive member 40 is within an allowable range by stopping the developing sleeve 43a.

  As a result, it is possible to keep the friction resistance between the cleaning blade 46a and the photoreceptor 40 low without causing fatigue of the developer or the like, and it is possible to continuously form high-quality images. It becomes.

  FIG. 5 is a flowchart of control by the control means 100.

  In STEP1, the photosensitive member 40 is rotationally driven at a predetermined normal V1, and in STEP2, the developing sleeve 43a is rotationally driven at a normal speed V2.

  In STEP 3, the exposure unit 42 is driven to expose the photoconductor 40 to form an electrostatic latent image on the photoconductor 40.

  In STEP 4, the presence or absence of image data is monitored, and the process ends if there is no image data. If there is image data, the presence / absence of insertion printing is monitored (STEP 5), and if there is no insertion printing, the process returns to STEP 3. If there is insertion printing, the process proceeds to STEP 6 and the rotation driving of the developing sleeve 43a is stopped.

  After the development sleeve 43a is stopped, the end of the insertion printing is monitored (STEP 7). When the development sleeve 43a is completed, the process returns to STEP 2, and the development sleeve 43a is rotationally driven at the normal speed V2 to perform image formation.

  If the insertion printing is not completed in STEP 7, the development sleeve 43a is stopped for a predetermined time by monitoring whether or not a predetermined time has elapsed in STEP 8.

  After a predetermined time has elapsed, in STEP 9, the developing sleeve 43a is rotationally driven at a speed V3 lower than the normal speed V2, and is continued until the insertion printing is completed.

  When the insertion printing is completed (YES in STEP 10), the process returns to STEP 2, and the developing sleeve 43a is rotationally driven at the normal speed V2, and the image formation is continued.

  The low-speed rotation time of the developing sleeve 43a set in STEP 8 is the time until the process of transporting a set number of image-formed sheets P is completed in the case of insertion printing.

  In addition to the developing sleeve, the rotating body for applying the lubricant to the surface of the photoreceptor can be a brush roller or the like, and a lubricant application roller for applying a lubricant such as a fatty acid metal salt to the photoreceptor can also be used.

  That is, as shown in FIG. 6, the lubricant application roller 45 provided upstream of the cleaning means 46 can be used as a rotating body for applying the lubricant, and the developing sleeve and the lubricant application roller are used in combination. May be. In this case, the lubricant application roller is driven to rotate at a normal rotational speed in the image forming area, and the lubricant application roller that is driven to rotate at a rotational speed lower than the normal rotational speed is controlled in a predetermined non-image forming area. .

  Further, as the image bearing member, there is an intermediate transfer member in addition to the photosensitive member, and by controlling the rotation of the rotating member for applying the lubricant to the intermediate transfer member as described above, the intermediate transfer member is not cleaned properly. In addition, it is possible to prevent early deterioration of the cleaning blade of the intermediate transfer member cleaning unit.

  The predetermined non-image forming area where the rotating body is controlled as shown in FIG. 4B and FIG. 5 is easily long between images in continuous image formation because of work in a part other than the image forming unit. This is a case where an image interval is formed, and examples thereof include the insertion printing described above and bookbinding in the post-processing apparatus B.

  In FIG. 5, the control unit 100 monitors the length of the non-image forming area and performs low speed control. However, as another control method, when insertion printing or bookbinding is performed, these operations are required. It is also possible to calculate the time, drive the rotating body at a low speed for the calculated time, and switch to the normal speed at the end of these operations.

1 is a diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of an image forming unit 4 in the image forming apparatus illustrated in FIG. 1. 2 is a block diagram of a control system of the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a sequence chart of control in the image forming apparatus according to the embodiment of the present invention. 3 is a flowchart of control in the image forming apparatus according to the embodiment of the present invention. It is a figure which shows the principal part of the other example of the image forming apparatus which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 4 Image forming part 41 Charging means 42 Exposure means 43 Developing means 43a Developing sleeve 44 Transfer / separation means 45 Lubricant application roller 46 Cleaning means 100 Control means

Claims (4)

In an image forming apparatus having an image forming unit that includes a developing unit having an image carrier and a developing sleeve, and continuously forms a toner image on the image carrier.
And a control unit that controls the developing sleeve. The control unit does not form a toner image by the image forming unit, and at least part of a predetermined non-image forming region in which the image carrier moves. An image forming apparatus, wherein the developing sleeve is controlled to rotate at a lower speed than in the forming region. In an image forming apparatus having an image carrier, an image forming unit that continuously forms a toner image on the image carrier, and a rotating body that applies a lubricant on the image carrier.
And a control unit that controls the rotating body. The control unit does not form a toner image by the image forming unit, and at least part of a predetermined non-image forming area in which the image carrier moves. An image forming apparatus that performs control to rotate the rotating body at a lower speed than in a forming area. The predetermined non-image forming area is an area in which the image carrier is operated without performing image formation by the image forming means in order to operate an operation unit other than the image forming means. The image forming apparatus according to claim 1. The control unit stops the rotating body at the head of the predetermined non-image forming area, and rotates the rotating body at the low speed when a predetermined period has elapsed. The image forming apparatus described in the item.

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