JP2010262022A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a problem resulting from an abnormal state of a cleaning blade during image formation, by detecting the abnormal state of the cleaning blade with a simple configuration as early as possible. <P>SOLUTION: An image forming apparatus includes: an image carrier rotated with a toner image carried thereon; a transfer means for transferring the toner image to a transfer material; and a cleaning device having a cleaning blade, which is brought into press contact with the image carrier after transfer has been performed and which cleans the image carrier. The image forming apparatus includes: a normal image formation mode for forming an image; and a blade test mode for setting conditions so as to easily causing a cleaning failure for checking an abnormal state of the cleaning blade, and displaying a cleaning state as a result of the setting of the conditions. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a cleaning device provided with a cleaning blade.

  The electrophotographic technology is a technology that is widely used in copiers, printers, facsimiles, and multi-function machines having these functions.

  In this electrophotographic technique, first, a photosensitive member is uniformly charged, and then a latent image is formed on the photosensitive member by a writing unit that performs exposure corresponding to image data, and the latent image is developed by a developing unit. Thus, a toner image that is a visualized image is formed. The toner image formed on the photosensitive member is transferred from the photosensitive member to a recording sheet or an intermediate transfer member as a transfer material by a transfer unit. The entire toner image formed on the photoconductor is preferably transferred to a recording paper or an intermediate transfer body, but in reality, a small amount of toner remains on the photoconductor after the transfer process is completed. In order to remove the transfer residual toner remaining on the photosensitive member, a cleaning device is provided.

  Generally, such a cleaning device is provided with a cleaning blade that scrapes off transfer residual toner from the surface of the photoreceptor. The cleaning blade is made of an elastic resin, for example, a polyurethane-based resin, and the edge of the tip is directed in the direction opposite to the moving direction of the photoconductor surface, and the edge and the vicinity of the edge are in contact with the photoconductor. Are arranged as follows. Therefore, the photosensitive member and the cleaning blade are in a rubbing relationship through a certain contact area, and the cleaning blade may cause problems related to the charging characteristics of the cleaning blade and the frictional resistance between the photosensitive member and the cleaning blade. is there.

  For example, when a toner having a polarity different from that of the cleaning blade comes into contact with a cleaning blade charged to a certain polarity, the toner adheres to the cleaning blade due to electrostatic attraction and is gradually accumulated. The accumulated toner is transferred to the photosensitive member that is rubbed with the cleaning blade at some occasion and adheres firmly to the surface thereof. This adhered toner triggers further toner and external additives to adhere to the surface of the photoconductor, and the toner and external additives firmly adhered to the surface of the photoconductor deform the edge of the cleaning blade that rubs the surface of the photoconductor. There is a concern of causing damage.

  Further, when an image with a low printing rate is continuously developed and the toner image is transferred, residual toner on the surface of the photoreceptor is also reduced, so that the edge of the cleaning blade is turned over. It becomes easy. Technology that detects abnormalities at the edge of the cleaning blade with a piezoelectric element provided on the cleaning blade, changes the pressure on the photosensitive member of the cleaning blade, and detects the state of the cleaning blade to generate a signal It is disclosed (for example, see Patent Document 1).

  However, paper dust generated from the recording paper may remain on the surface of the photoconductor in addition to the transfer residual toner. When the paper dust is sandwiched between the edges of the cleaning blade, the piezoelectric element is caused by edge turning. There is a problem that it cannot be clearly detected like an abnormality. Further, in the configuration using the piezoelectric element, the mechanism is complicated and the cost is increased.

  On the other hand, if images with a low printing rate continue, the friction between the photoconductor and the cleaning blade becomes large in addition to turning the cleaning blade due to the lack of residual toner on the photoconductor. The inconvenience of reducing the service life occurs. A technique for forming a black belt-like image in a non-image area (hereinafter referred to as a paper gap) between images on a photosensitive member as a countermeasure for problems caused by a shortage of toner remaining after transfer such as turning over of the cleaning blade and short life. Has been proposed (see, for example, Patent Document 2). When image formation with a low printing rate continues for a certain number of sheets or more, a black belt-like toner image (toner band) is formed in the non-image area (inter-paper portion) between the images on the photoreceptor, and the toner necessary for this image is formed. It is a proposal to send to the cleaning blade.

  This technology forms a black belt, which is a toner image for cleaning, between the images transferred to the transfer material on the photoconductor (inter-paper area), and a fixed amount determined by the amount of toner used for the black belt image The toner is sent to the cleaning blade. That is, by constantly sending a predetermined amount of toner to the cleaning blade, an attempt is made to prevent the occurrence of problems such as friction due to the lack of transfer residual toner on the photoreceptor. The formation of the black belt image eliminates the phenomenon that the toner stays in the developing device for a long time because a constant amount of toner is supplied from the developing device even when images with a low printing rate are continuous. It is also a measure to prevent the deterioration of the.

  However, if the toner amount sent to the cleaning device by the black belt image is insufficient, the predetermined purpose cannot be achieved, and if a toner exceeding a desired amount is sent at a time, a cleaning defect is caused. Therefore, it is necessary that a desired amount of toner is sent to the cleaning blade at a desired timing. However, there is no guarantee that a toner image of the same density will always be formed even if a black belt-like image is formed under the same imaging conditions due to changes in the characteristics of the photoconductor and developer with the environment and changes over time. There may be a problem that a necessary amount of toner is not sent to the cleaning blade. In addition, only the formation of a black belt-like image is a fundamental solution to the above-described problems that toner and external additives adhere to the surface of the photoconductor and that paper dust is caught between the edges of the cleaning blade. It is not.

Japanese Patent Laid-Open No. 6-67585 Japanese Patent Laid-Open No. 8-11536

  The present invention solves the above-mentioned problems, makes it difficult to detect paper dust and the like, and without using a piezoelectric element that increases the cost. It can also cope with the problem of being caught between the edges of the cleaning blade. That is, an object of the present invention is to quickly detect an abnormality of the cleaning blade and prevent occurrence of a problem due to the abnormality of the cleaning blade at the time of image formation in spite of a simple configuration.

  The object is achieved by the following invention.

1. An image carrier that carries and rotates a toner image;
Transfer means for transferring a toner image to a transfer material;
A cleaning device provided with a cleaning blade that presses and cleans the image carrier after transfer, and
A normal image forming mode for forming an image;
An image forming system comprising: a blade test mode in which a condition setting that is likely to cause a cleaning failure for confirming abnormality of the cleaning blade is performed, and a cleaning state is displayed as a result of the condition setting. apparatus.

2. A belt-shaped image forming mode for forming a belt-shaped image that is not transferred to a transfer material in a non-image area located before and after the rotation direction of the image carrier with respect to the toner image carried on the image carrier,
The transfer means has voltage application means with variable polarity and voltage,
The voltage applying unit applies a voltage having the same polarity as that of toner in the normal image forming mode to the belt-shaped image formed on the image carrier, and as the condition setting in the blade test mode. 2. The image forming apparatus according to 1, wherein a voltage having the same polarity as the toner and having a larger absolute value than a voltage applied to the belt-like image in the normal image forming mode is applied.

  3. 3. The image forming apparatus according to 1 or 2, wherein as the condition setting, a pressure at which the cleaning blade is pressed against the image carrier in the blade test mode is smaller than a pressure in the normal image forming mode.

  4). 4. The image forming apparatus according to any one of claims 1 to 3, wherein in the blade test mode, as an indication of the cleaning state, an image for determining a cleaning state is formed on a transfer material and discharged.

5). The image forming apparatus detects a cleaning state of the image carrier, a cleaning state detection unit disposed opposite to the image carrier, or a cleaning that detects a cleaning state of a white background portion of an image-formed transfer material. State detection means;
Display means for displaying the cleaning state of the image carrier or the transfer material as an indication of the cleaning state;
In the blade test mode, the cleaning state detection means detects the cleaning state of the image carrier or the transfer material and compares it with a preset reference value of the cleaning state, and the detected cleaning state is the cleaning state. Any one of 1 to 4 above, wherein if the level is lower than a reference value of the state, the display means displays a message indicating that the cleaning blade state needs to be confirmed as the display of the cleaning state. The image forming apparatus described in the item.

  6). The detection of the cleaning state detected by the cleaning state detection means is performed by measuring the image density of a white background portion in the image carrier cleaned after image formation or the transfer material on which image formation has been performed. 6. The image forming apparatus as described in 5 above.

  7). The cleaning state detection by the cleaning state detection unit is performed when the image forming apparatus is turned on or when the cumulative number of image formation reaches a preset reference value of the cumulative number. Or the image forming apparatus according to 6;

  8). The detection of the cleaning state by the cleaning state detection unit is performed when the cumulative number of image formations reaches a preset reference value of the cumulative number of sheets, and the number of times of detection of the cleaning state by the cleaning state detection unit is 7. The image forming apparatus according to 5 or 6, wherein the frequency is set so as to increase as the cumulative number of sheets increases.

  According to the present invention, it is possible to prevent the occurrence of an image defect due to the abnormality of the cleaning blade at the time of image formation by quickly detecting the abnormality of the cleaning blade with a simple configuration.

1 is a schematic configuration diagram for explaining the configuration and operation of an embodiment of an image forming apparatus according to the present invention. It is a block diagram for demonstrating the control system of the image forming apparatus G provided with the blade test mode which concerns on this invention. FIG. 6 is a development view of the surface of the photoconductor 31 for explaining a belt-like image formed on the photoconductor 31 in the belt-like image forming mode according to the present invention. It is a typical block diagram for demonstrating the structure and operation | movement in the blade test mode which concern on this invention. It is a flowchart which shows the procedure of operation | movement of 3rd Embodiment of the blade test mode which concerns on this invention. It is a flowchart which shows the procedure of operation | movement of 4th Embodiment of the blade test mode which concerns on this invention. It is a flowchart for demonstrating the procedure of operation | movement about 5th Embodiment of the blade test mode which concerns on this invention.

  Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described with reference to FIG. 1, but the application of the present invention is not limited to this embodiment.

  FIG. 1 is a schematic configuration diagram for explaining the configuration and operation of an embodiment of an image forming apparatus according to the present invention.

  The image forming apparatus G has an automatic document feeder F at the top of the main body. The main body includes a reading unit 1, a writing unit 2, an image forming unit 3, an operation display unit 4, a paper feeding unit 5, and a paper discharge refeed. The paper unit 6, the fixing unit 7, the control unit C, and the like are included.

  The automatic document feeder F feeds the documents placed on the document table 11 to the document conveying means 13 one by one by the document separating means 12, and the document conveying means 13 conveys the sent documents to the document discharging means 14. Then, the document discharge means 14 discharges the sent document to the document discharge table 15. The document image is read by a slit 21 provided in the document conveyance path, which is a document image reading position of the reading unit 1.

  When reading images on both sides of the document, the document which has been read on the first surface is reversed by the document reversing means 16 having a pair of rollers, and is sent again to the document conveying means 13 to re-feed the second surface. Reading is done. The document that has been read is discharged to the document discharge table 15.

  The reading unit 1 is a unit that obtains image data from an original image. The original image irradiated with light by the lamp 231 at the position of the slit 21 is a first mirror unit 23, a second mirror unit 24, and an imaging lens. 25, an image is formed on the image sensor 26 of the line CCD. The signal output from the image sensor 26 is A / D converted by the image processing unit of the control means C, subjected to processing such as shading correction and image compression, and is stored in the memory M as image data.

  The writing means 2 is a rotating image carrier that is uniformly charged by the charging means 32 by a laser beam and a polygon mirror based on image data that has been called from the memory M and subjected to predetermined image processing. The surface of the photosensitive member 31 is scanned. By this scanning, an electrostatic latent image corresponding to the original image is formed on the surface of the photoreceptor 31.

  The electrostatic latent image is reversely developed by a developing unit 34 as a developing unit of the image forming unit 3, and a toner image is formed on the photoreceptor 31.

  Corresponding to the timing of toner image formation, the recording paper P is fed from the manual paper feeding means 55 or the paper feeding means 5 having a cassette or tray for storing the recording paper P as a transfer material. The fed recording paper P is conveyed by a conveying roller 56, and is synchronized by the timing roller 39 for alignment with the toner image formed on the photosensitive member and sent out to the transfer area.

  In the transfer area, the toner image formed on the surface of the photoreceptor 31 is transferred to the recording paper P charged to the opposite polarity by the action of the transfer means 35 and the voltage applying means E1. The recording paper P carrying the toner image is separated from the surface of the photoreceptor 31 by the action of the separating unit 36 and sent to the fixing unit 7. In the fixing unit 7, the recording paper P carrying the toner image is conveyed while being heated and pressurized by the heating roller 71 and the pressure roller 72, and the toner image is fixed on the recording paper P. Sent out.

  When the recording paper P is reversed and sent out, the switching guide 62 guides the recording paper P to the paper discharge / refeed means 6, switches the recording paper P back to the discharge roller 63. Further, when forming an image on both sides of the recording paper P, the recording paper P that has been fixed on the first surface is guided to the paper discharge refeeding means 6 by the switching guide 62 and reversed by the reversing unit 65. After that, the sheet is fed to a conveyance path 66 for paper feeding and used for image formation on the second surface.

  On the other hand, the surface of the photoconductor 31 after the transfer of the toner image onto the recording paper P is prepared for the next image formation after the residual toner is removed by the cleaning device 37.

  A control unit C provided in the image forming apparatus G incorporates a memory M and controls the operation of each unit of the image forming apparatus G.

  FIG. 2 is a block diagram for explaining a control system of the image forming apparatus G having the blade test mode according to the present invention.

  The control means C is a computer system having a CPU, a memory M, an arithmetic unit (not shown), an I / O port, a communication interface, etc., and also has a circuit for driving each means. Each unit is controlled by executing a program corresponding to each job such as an image forming mode and a blade test mode stored in the memory M.

  In FIG. 2, the control means C receives information from the power switch SW, the total counter TC, the cleaning state detection means 10a, 10b, the operation display means 4, etc., and receives the image forming mode, blade test mode, Alternatively, a belt-like image forming mode or the like is selected. When the image forming mode or the belt-like image forming mode is selected, the operation of each part of the image forming apparatus is controlled. When the blade test mode is selected, the operation of the voltage applying unit E1, the cleaning blade pressing unit BA, the blade state display unit BH, the determination image forming unit GS, and each part of the image forming apparatus is controlled. Although the image forming mode and the blade test mode cannot be selected at the same time, when the belt-like image forming mode is selected, either the image forming mode or the blade test mode can be selected at the same time.

  The image density detection sensors 10a and 10b as cleaning state detection means detect the image density of the white background portion of the photoreceptor 31 or the recording paper P, and are an automatic image determination device using an optical sensor or a CCD (the image is converted into a dot pattern). Apparatus for detecting and determining the density of an image by decomposition. The image density detection sensors 10a and 10b detect the image density of the white background portion of the photoreceptor 31 and the recording paper P and output a signal to the control means C. Upon receipt of the signal, the control means C compares the detected value with the image density reference value to determine whether there is a cleaning failure. If an abnormality is found, the blade status display means BH (described later) indicates that cleaning blade confirmation is required. To give out.

  The operation display unit 4 is an input unit that operates the image forming apparatus G, which includes various buttons, a touch panel, a display unit, and the like disposed in the image forming apparatus G. The operation display means 4 can also be provided in a personal computer or the like connected online from the outside.

  The total counter TC is a counter that counts the cumulative number of images formed by the image forming apparatus G.

  The voltage applying means E1 is a DC high-voltage power supply device with variable polarity and voltage, and applies a voltage having a polarity opposite to that of the toner in the normal image forming mode and a voltage having the same polarity as that of the toner in the band-shaped image forming mode. .

  The blade status display means BH as the display means according to the present invention is disposed in the operation display means 4, and it is necessary to check the cleaning blade status when the cleaning state of the image forming apparatus G is estimated to be poor. This is a display means for displaying a message to the effect. The blade status display means BH is displayed on the operation display means 4 by displaying characters on the liquid crystal or lamp display. The determination image forming unit GS calls up the cleaning determination image stored in the memory M in advance and forms an image on the recording paper P when the cleaning state in the blade test mode is to be confirmed. And an image forming unit including each unit of the image forming apparatus. The image formed on the recording paper P is automatically detected by the image density detection sensor 10b or is discharged as it is and visually judged. The configuration of the cleaning blade pressure contact means BA will be described later with reference to FIG.

  The belt-like image forming mode is a mode that is used together when a document image with a low printing rate is continuously formed in the normal image forming mode or when the blade test mode is selected. In this mode, a belt-like image is formed in the inter-paper portion of the image. This belt-like image is an image formed only on the photoreceptor 31 and is not transferred to the recording paper P.

  FIG. 3 is a development view of the surface of the photoreceptor 31 for explaining the belt-like image forming mode according to the present invention.

  The images Z1 and Z2 are toner images continuously transferred onto the recording paper P and move in the rotation direction X (paper transport direction) of the photoconductor 31 as the photoconductor 31 rotates. It is formed before and after the two toner images (between sheets). Since the belt-like image is an image that is not transferred onto the recording paper P, when the surface of the rotating photosensitive member 31 carrying the belt-like image reaches the position of the transfer device 35, the transfer device 35 is given a voltage having the same polarity as the toner. The By applying a voltage having the same polarity as the toner to the transfer means 35, the toner in the belt-like image portion is prevented from scattering from the photoreceptor 31 to the outside. In particular, the image formation with a configuration using an intermediate transfer belt or a transport belt is used. In the apparatus, it is necessary to strongly attract the toner to the photoreceptor 31 side.

  In the embodiment, the belt-like image is set to have a maximum density at which the toner adhesion amount is maximized, but may be set to a lower constant density.

  The belt-like image forming mode is used in combination with the normal image forming mode when a document having a low printing rate is continuous, so that an appropriate amount of toner is sent to the cleaning blade 370 (see FIG. 4). The friction with the can be reduced and wear and damage can be suppressed. Further, by forming a belt-like image, a predetermined amount of toner is supplied, so that toner retention in the developing device 34 is reduced, circulation is smoothed, and toner deterioration is suppressed. The formation of a strip image in the blade test mode will be described later with reference to FIG.

  FIG. 4 is a schematic configuration diagram for explaining the configuration and operation in the blade test mode according to the present invention. In the blade test mode, the cleaning conditions for the photoconductor 31 are set to be strict so that a cleaning failure is likely to occur. Abnormalities in the cleaning blade 370 are detected and dealt with promptly to prevent a cleaning failure during image formation. It is. As countermeasures against the abnormality of the cleaning blade 370, there are confirmation of the state of the cleaning blade 370, removal of foreign matter, replacement of the cleaning blade 370, and the like. The condition setting items that are likely to cause a cleaning failure include the pressure at which the cleaning blade 370 presses against the photoreceptor 31, the transfer voltage applied to the belt-like image formed between the sheets of the photoreceptor 31, and the image on the photoreceptor 31. The specification of the test pattern image to be formed can be considered.

  In FIG. 4, the developing device 34 includes a developing roller 340, and a high voltage power source (not shown) is connected to the developing roller 340, and a bias voltage is applied as a developing bias. The developing bias is applied to the photosensitive drum 31 via the developing roller 41 by an AC power source and a DC power source (not shown). A high voltage power source (not shown) is connected to the charger 32.

  In the blade test mode, the voltage applying unit E1 applies a voltage having the same polarity as the toner to the belt-like image and having a value larger than that applied to the belt-like image in the normal image forming mode. In the blade test mode, the reason why a voltage having a larger value than that in the normal image forming mode is applied is that the toner is electrostatically attracted to the photosensitive member 31 by applying a larger voltage to the toner, This is to make it difficult to clean. That is, it is possible to prevent the occurrence of defective cleaning during image formation by quickly detecting and addressing an abnormality of the cleaning blade by creating a situation that is difficult to clean.

  Reference numerals 10a and 10b denote image density detection sensors as cleaning state detection means according to the present invention, which detect a cleaning failure in the blade test mode. The image density detection sensor 10a indicates the cleaned state of the surface of the photoconductor 31 after cleaning, and the image density detection sensor 10b indicates that no toner remains on the white background portion of the surface of the recording paper P to which the toner image is transferred from the photoconductor 31. Is detected as an image density value. The image density detection sensor 10 a is disposed on the downstream side in the rotation direction of the photoconductor 31 of the cleaning device 37 around the photoconductor 31, and the image density detection sensor 10 b is disposed on the downstream side of the transfer unit 35.

  The first embodiment of the blade test mode according to the present invention relates to the cleaning blade pressure contact means BA, and the pressure at which the cleaning blade 370 of the cleaning device 37 is pressed against the photosensitive member 31 is set smaller than that during normal image formation. Is. The cleaning blade pressure contact means BA includes a cleaning blade 370, a rotating shaft 371 that holds the cleaning blade 370 in a swingable manner in the rotation direction of the rotating shaft 371, and a variable torque that is coupled to the rotating shaft 371 via a gear (not shown). Drive motor M1. The rotating shaft 371 is configured to hold the cleaning blade 370 in a swingable manner and is connected to a drive motor M1 having a variable torque so that the cleaning blade 370 is pressed against the photosensitive member 31 by the rotational torque of the motor. That is, by making the torque of the drive motor M1 in the blade test mode smaller than that in normal image formation, the pressure of the cleaning blade 370 against the photosensitive member 31 is reduced, and cleaning failure is likely to occur.

  In an experiment in which the pressure of the pressure contact of the cleaning blade 370 to the photoconductor 31 is lowered to the normal 80%, when the cleaning blade 370 has an abnormality, the inventor moves in the rotation direction of the photoconductor 31 that does not occur at the normal pressure. The occurrence of streaky toner contamination is confirmed. The abnormality of the cleaning blade 370 here refers to partial wear, chipping of edges of about 20 to 30 μm, clogging of paper dust, and the like.

  According to the first embodiment of the blade test mode according to the present invention, the condition that the cleaning failure is likely to occur is set, so that the abnormality of the cleaning blade 370 can be detected quickly.

  In the second embodiment according to the blade test mode of the present invention, the voltage applied by the voltage applying means E1 connected to the transfer means 35 is applied to the belt-like image formed on the photoconductor 31 during normal image formation. The voltage has a larger absolute value than the voltage of.

  The voltage applied by the voltage applying means E1 in the second embodiment of the blade test mode to the belt-like image (see FIG. 3) formed on the photoconductor 31 is a document with a low printing rate during normal image formation. It is set to a value having a larger absolute value than the voltage applied in the case of continuous. By setting the voltage to be applied to the belt-like image in the blade test mode to a large absolute value, the force of electrostatically attracting the toner to the photoconductor 31 is increased, and the cleaning blade 370 is abnormal as an environment in which cleaning failure is likely to occur. This is because it can be detected quickly.

  In the first or second embodiment of the blade test mode according to the present invention, the control unit C drives the determination image forming unit GS, and uses the laser light a for testing as a cleaning state determination on the photosensitive member 31. A pattern image is formed. The determination image forming unit GS includes a writing unit 2 that calls a test pattern image stored in the memory M in advance and writes it with a laser beam a, a charging unit 32, a developing device 34, and the like. The density of the white background portion of the test pattern image is detected by the image density detection sensor 10a as the cleaning state detecting means, and the detected value is compared with the reference value. When the detected value is larger than the reference value (the image density is high), the control unit determines that the cleaning state is bad and that there is a high possibility that the cleaning blade 370 is malfunctioning, and the cleaning blade state confirmation necessity display is displayed. The blade state display means BH is instructed to output.

  As a means for detecting the cleaning state, a configuration using the image density detection sensor 10a for detecting the image density of the test pattern image formed on the photosensitive member 31, and the test pattern image is transferred to the recording paper P to obtain a white background portion. There is a configuration for detecting the concentration of the. In the configuration of transferring to the recording paper P, the density of the white background portion of the transfer means 35 of the recording paper P to which the test pattern image has been transferred is detected using the image density detection sensor 10b disposed downstream in the paper transport direction. It is the composition of doing.

  As another means for detecting the cleaning state, the image density of the test pattern image formed on the photosensitive member 31 is transferred to the recording paper P without automatically detecting the cleaning state, and the recording paper P is transferred to the recording paper P. It may be determined that the discharge is performed as it is, and the determination may be made visually.

  As the test pattern image of this embodiment, an image with a heavy load on the cleaning blade 370 and easily causing a cleaning failure, an image in which half of the image is black and the other half is white, or an image portion has a low printing rate. An image that forms a band-like image in a non-image portion (inter-paper portion) can be considered.

  According to the second embodiment of the blade test mode according to the present invention, as in the first embodiment, a condition that causes a cleaning failure is set, so that an abnormality of the cleaning blade 370 can be detected quickly.

  It is a typical block diagram for demonstrating the structure and operation | movement in the blade test mode which concern on this invention. The third embodiment of the blade test mode relates to the timing for selecting the blade test mode, and has a configuration in which the blade test mode is selected every time the image forming apparatus G is turned on. Hereinafter, a description will be given with reference to the flowchart shown in FIG.

  FIG. 5 is a flowchart showing the operation procedure of the third embodiment of the blade test mode according to the present invention.

  In FIG. 5, the control unit C selects and implements the blade test mode from the memory M by turning on the power switch SW of the image forming apparatus G (step S11) (step S12).

  Next, the control means C causes the image density detection sensor 10a or 10b to detect the image density of the white background portion of the test pattern image, and determines whether or not the cleaning state is normal by comparing with a preset reference value of the image density. (Step S13). If the detected value is smaller than the reference value (Yes at Step S13), it is determined as normal, and the process proceeds to Step S15. If the detected value is larger than the reference value (No at Step S13), it is determined as abnormal and the process proceeds to Step S14. move on.

  In step S14, the control unit C instructs the blade state display unit BH to display a message indicating that the cleaning blade state is necessary. The cleaning blade state is confirmed by displaying the cleaning blade state confirmation necessity, and if necessary, the cleaning blade 370 is replaced (step S14).

  Finally, in step S15, the control means C instructs the blade state display means BH to turn off the display of the cleaning blade state confirmation necessity, and ends the blade test mode (step S15).

  According to the third embodiment of the blade test mode according to the present invention, since the blade test mode is automatically selected by the operation of turning on the power, the abnormality of the cleaning blade 370 is detected promptly, so that It is possible to prevent a problem that image formation is poor. For example, when the power is turned on at the start of work in the morning, it is possible to reduce the risk that the image formation of the day will result in poor cleaning. In addition, when an abnormality is detected in the cleaning state in the blade test mode, the cleaning blade state confirmation necessity display is displayed, so that the cleaning blade state is confirmed before the subsequent image formation. The occurrence of image defects can be prevented.

  In this embodiment, the timing for selecting the blade test mode is the power-on timing, but it may be the timing for inserting the plug of the image forming apparatus G in place of the power-on.

  The fourth embodiment in the blade test mode according to the present invention is a configuration relating to the timing for selecting the blade test mode, and the blade test is performed when the cumulative number of image forming sheets of the image forming apparatus G reaches a preset reference value. This is a configuration that is performed by selecting a mode. Hereinafter, a description will be given using the flowchart shown in FIG.

  FIG. 6 is a flowchart showing an operation procedure of the fourth embodiment of the blade test mode according to the present invention.

  In FIG. 6, in step S21, the image forming apparatus G is in a normal image forming mode, and normal image formation is performed (step S21). Next, based on the information on the number of sheets from the total counter TC of the image forming apparatus G, the control unit C determines whether or not the cumulative number of formed images has reached the timing for performing the blade test mode (reference value for the cumulative number of formed images). Judgment is made (step S22). This determination is made by comparing the reference value of the cumulative image formation number stored in advance in the memory M with the number information from the total counter TC. When the number of the total counter TC has not reached the reference value (No at Step S22), the process returns to Step S21 and normal image formation is performed again. When the total counter TC reaches the reference value (Yes at Step S22), the process proceeds to Step S23.

  In step S23, the control unit C causes the image forming apparatus G to select and implement the blade test mode (step S23). Next, the control means C causes the image density detection sensor 10a or 10b to detect the image density of the white background portion of the test pattern image, and determines whether or not the cleaning state is normal by comparing with a preset reference value of the image density. (Step S24). When the detected value is smaller than the reference value (Yes at Step S24), it is determined as normal and the process proceeds to Step S26. When the detected value is larger than the reference value (No at Step S24), it is determined as abnormal and the process proceeds to Step S25. move on.

  In step S25, the control unit C instructs the blade state display unit BH to display a message indicating that the cleaning blade state is necessary. The cleaning blade state is confirmed by displaying the cleaning blade state confirmation necessity, and if necessary, the cleaning blade 370 is replaced (step S25).

  Finally, in step S26, the control unit C instructs the blade state display unit BH to turn off the display of the cleaning blade state confirmation necessity, and ends the blade test mode (step S26).

  According to the fourth embodiment relating to the blade test mode of the present invention, since the blade test mode is set to be executed based on the cumulative number of image formations, it is possible to periodically detect an abnormality in the cleaning blade 370. it can.

  In the fifth embodiment of the blade test mode according to the present invention, the number of times of detection for detecting whether or not the cumulative number of image formations of the image forming apparatus G has reached the execution time of the blade test mode is set as the cumulative number of image formations. As the number increases, the frequency is set to increase. For example, the initial detection is performed every 50,000 prints, and when the cumulative number of image formation exceeds 50% of the average durable number of the cleaning blade 370, the detection frequency is detected every 10,000 prints. It is the composition which changes the frequency of. Hereinafter, a description will be given using the flowchart shown in FIG.

  FIG. 7 is a flowchart for explaining the procedure of the operation in the fifth embodiment of the blade test mode according to the present invention.

  In FIG. 7, in step S31, the image forming apparatus G is in a normal image forming mode, and normal image formation is performed (step S31). Next, the control means C uses the information from the total counter TC of the image forming apparatus G to perform the first stage when the cumulative number of image formations implements the blade test mode (the reference value for the first stage of the total number of image formations). ) Is determined (step S32). This determination is made by comparing the first-stage reference value of the total number of image formation sheets stored in the memory M in advance with the information on the total number of sheets from the total counter TC. When the cumulative number of total counters TC has not reached the reference value (No at Step S32), the process returns to Step S31 and normal image formation is performed again. When the cumulative number of the total counter TC reaches the reference value (Yes at Step S32), the process proceeds to Step S33.

  In step S33, the control unit C causes the image forming apparatus G to select and implement the blade test mode (step S33). Next, the control means C causes the image density detection sensor 10a or 10b to detect the image density of the white background portion of the test pattern image, and determines whether or not the cleaning state is normal by comparing with a preset reference value of the image density. (Step S34). If the detected value is smaller than the reference value (Yes at Step S34), it is determined as normal, and the process proceeds to Step S35. If the detected value is larger than the reference value (No at Step S34), it is determined as abnormal and the process proceeds to Step S42. move on. In step S35, the control means C ends the blade test mode (step S35). Next, the control unit C selects a normal image forming mode and causes the image forming apparatus G to perform normal image formation (step S36).

  Next, based on the number information from the total counter TC of the image forming apparatus G, the control unit C shifts to the second stage in which the cumulative number of image formations implements the blade test mode (to the second stage of cumulative number of image formations). Is determined (step S37). This determination is made by comparing the reference value for the transition to the second stage of the cumulative image formation number stored in advance in the memory M and the cumulative number information from the total counter TC. When the cumulative number of the total counter TC has not reached the reference value for shifting to the second stage (No at Step S37), the process returns to Step S36 and normal image formation is performed again. When the cumulative number of the total counter TC reaches the reference value for shifting to the second stage (Yes at Step S37), the process proceeds to Step S38. In step S38, the control unit C shifts the frequency of detection by the total counter TC when the blade test mode is performed to the second stage higher than the first stage, and performs normal image formation on the image forming apparatus G. (Step S38).

  Next, the control means C uses the information on the number of sheets from the total counter TC of the image forming apparatus G to execute the second stage when the cumulative number of image formations implements the blade test mode (the second stage implementation of the total number of image formations). Is determined (step S39). This determination is made by comparing the reference value of the second stage implementation of the cumulative number of image formation sheets stored in the memory M in advance with the cumulative number information from the total counter TC. When the total number of the total counter TC has not reached the reference value for the second stage execution (No at Step S39), the process returns to Step S38 and normal image formation is performed again. When the cumulative number of the total counter TC reaches the reference value for the second stage implementation (Yes at step S39), the process proceeds to step S40.

  In step S40, the control means C selects and implements a blade test mode (step S40). Next, the control means C causes the image density detection sensor 10a or 10b to detect the image density of the white background portion of the test pattern image, and determines whether or not the cleaning state is normal by comparing with a preset reference value of the image density. (Step S41). If the detected value is smaller than the reference value (Yes at step S41), it is determined as normal, and the process returns to step S38 to perform normal image formation. If the detected value is larger than the reference value (No at Step S41), it is determined that there is an abnormality and the process proceeds to Step S42.

  In step S42, the control unit C instructs the blade state display unit BH to display a message indicating that the cleaning blade state is necessary. The cleaning blade state is confirmed based on the display of the cleaning blade state confirmation necessity, and if necessary, the cleaning blade 370 is replaced (step S42).

  Finally, in step S43, the control unit C instructs the blade state display unit BH to turn off the display of the cleaning blade state confirmation necessity, and ends the blade test mode (step S43).

  According to the fifth embodiment of the blade test mode of the present invention, the frequency is set so as to increase as the cumulative number of image formations increases. Can be detected.

4 Operation display means C Control means G Image forming apparatus M Memory P Recording paper a Laser light X Rotating direction of photoconductor 31 (paper transport direction)
10a Image density detection sensor (cleaning state detection means)
10b Image density detection sensor (cleaning state detection means)
31 Photosensitive drum (image carrier)
35 Transfer means 37 Cleaning device 370 Cleaning blade BA Cleaning blade pressure contact means BH Blade state display means (display means)
E1 Voltage applying means GS Image forming means for determination M1 Drive motor SW Power switch TC Total counter

Claims (8)

An image carrier that carries and rotates a toner image;
Transfer means for transferring a toner image to a transfer material;
A cleaning device provided with a cleaning blade that presses and cleans the image carrier after transfer, and
A normal image forming mode for forming an image;
An image forming system comprising: a blade test mode in which a condition setting for causing a cleaning failure for confirming an abnormality of the cleaning blade is performed, and a cleaning state is displayed as a result of the condition setting. apparatus. A belt-shaped image forming mode for forming a belt-shaped image that is not transferred to a transfer material in a non-image area located before and after the rotation direction of the image carrier with respect to the toner image carried on the image carrier,
The transfer means has voltage application means with variable polarity and voltage,
The voltage applying unit applies a voltage having the same polarity as that of toner in the normal image forming mode to the belt-shaped image formed on the image carrier, and as the condition setting in the blade test mode. The image forming apparatus according to claim 1, wherein a voltage having the same polarity as the toner and having a larger absolute value than a voltage applied to the belt-like image in the normal image forming mode is applied.   3. The image forming apparatus according to claim 1, wherein, as the condition setting, a pressure at which the cleaning blade is pressed against the image carrier in the blade test mode is smaller than a pressure in the normal image forming mode. .   4. The image forming apparatus according to claim 1, wherein, in the blade test mode, an image for determining a cleaning state is formed on a transfer material and discharged as an indication of the cleaning state. 5. The image forming apparatus detects a cleaning state of the image carrier, a cleaning state detection unit disposed opposite to the image carrier, or a cleaning that detects a cleaning state of a white background portion of an image-formed transfer material. State detection means;
Display means for displaying the cleaning state of the image carrier or the transfer material as an indication of the cleaning state;
In the blade test mode, the cleaning state detection means detects the cleaning state of the image carrier or the transfer material and compares it with a preset reference value of the cleaning state, and the detected cleaning state is the cleaning state. 5. The display device according to claim 1, wherein if the level is lower than a reference value of the state, the display unit displays a message indicating that the cleaning blade state needs to be confirmed as the display of the cleaning state. 2. The image forming apparatus according to item 1.   The detection of the cleaning state detected by the cleaning state detection means is performed by measuring the image density of a white background portion in the image carrier cleaned after image formation or the transfer material on which image formation has been performed. The image forming apparatus according to claim 5.   The cleaning state is detected by the cleaning state detection unit when the image forming apparatus is turned on or when the cumulative number of image formation reaches a preset reference value of the cumulative number. The image forming apparatus according to 5 or 6.   The detection of the cleaning state by the cleaning state detection unit is performed when the cumulative number of image formations reaches a preset reference value of the cumulative number of sheets, and the number of times of detection of the cleaning state by the cleaning state detection unit is The image forming apparatus according to claim 5, wherein the frequency is set so as to increase as the cumulative number of sheets increases.

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