JP2006098434A - Image forming apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can perform a satisfactory printing processing by preventing the occurrence of an image defect caused by products generated resulting from a charging operation, and to provide an image forming method. <P>SOLUTION: A refresh blade 251 is disposed so as to freely come in contact with and separate from the surface of a latent image carrier. During the printing processing, the refresh blade 251 is apart from the latent image carrier. This securely prevents image disturbance caused by the refresh blade 251 and makes it possible to carry out the printing processing satisfactorily. By bringing the refresh blade 251 into contact with the surface of the latent image carrier as required when the printing processing is not carried out (namely, in a non-printing state), the surface layer of the latent image carrier is removed by the refresh blade 251, so that the latent image carrier is refreshed. Thus, products generated resulting from a charging operation are removed by the refresh processing and the occurrence of an image defect is prevented, and the satisfactory printing processing is possible as a result. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention performs printing by charging a latent image carrier, forming a latent image on the latent image carrier, developing the toner on the latent image, and transferring the toner image formed by the toner development onto an intermediate transfer medium. The present invention relates to an image forming apparatus and an image forming method for executing processing.

  2. Description of the Related Art Conventionally, in an image forming apparatus that forms an image by electrophotography or the like, after the surface of a latent image carrier such as a photoconductor is uniformly charged by a charging member, the surface of the latent image carrier is irradiated with a light beam. Thus, an electrostatic latent image is formed. The electrostatic latent image on the latent image carrier is developed with toner carried on the developing roller of the developing unit to form a toner image. The toner image is primarily transferred to an intermediate transfer medium such as an intermediate transfer belt or an intermediate transfer drum, and then the primary transfer toner image is secondarily transferred to a sheet-like recording material such as copy paper or transfer paper. The Further, the toner image transferred to the recording material is fixed by the fixing unit, and an image is formed on the recording material.

  In recent years, a cleaner that removes residual toner after transfer by reducing the toner remaining on the latent image carrier after the primary transfer by increasing the transfer efficiency from the latent image carrier to the intermediate transfer medium has been developed. A technique to be omitted has been proposed (see, for example, Patent Document 1).

JP 2004-93580 A ([0016], [0017])

  By the way, in the image forming apparatus, it is necessary to charge the surface of the latent image carrier in order to perform the printing process. When the charging operation is performed, a large amount of ozone is generated and discharge products such as nitrogen oxides are generated. May be generated. As described above, when the discharge product generated by the charging operation adheres to the surface of the latent image carrier, this may adversely affect image formation. More specifically, when a discharge is generated by the charging operation and, for example, nitrogen oxides are formed, the nitrogen oxides react with moisture in the air to generate nitric acid and react with metals. Metal nitrate is produced. If the nitric acid or nitrate is formed into a thin film on the surface of the latent image carrier, the electrostatic latent image on the surface of the latent image carrier may be broken. As a result, an abnormal image appears as if the image has flowed, and good printing processing may not be performed.

  The occurrence of such an abnormal image greatly depends on the surrounding environment of the apparatus, particularly the surrounding environment of the latent image carrier. That is, film formation on the latent image carrier is closely related to moisture in the air, and abnormal images may appear prominently in a high humidity environment.

  The present invention has been made in view of the above problems, and provides an image forming apparatus and an image forming method capable of performing an excellent printing process by preventing an abnormal image from being generated due to a product generated in accordance with a charging operation. The purpose is to do.

  The image forming apparatus according to the present invention is configured so that the latent image carrier that rotates at a predetermined peripheral speed is in contact with the latent image carrier while rotating at substantially the same peripheral speed as the latent image carrier. A latent image carrier provided with a functional member provided to act on the latent image carrier and an intermediate transfer medium provided to come into contact with the latent image carrier while rotating at substantially the same peripheral speed as the latent image carrier. Image forming apparatus for performing printing process by charging body, forming latent image on latent image carrier, developing toner of latent image, and transferring toner image formed by toner development onto intermediate transfer medium In order to achieve the above object, the surface of the latent image carrier is provided so as to be able to be separated from and brought into contact with the surface of the latent image carrier, thereby removing the surface layer portion of the latent image carrier and removing the latent image carrier. Separate the refresh member that refreshes the image carrier and the refresh member. Drive means for driving, and control means for giving a drive command to the drive means to control the separation member abutment operation. The control means separates the refresh member from the latent image carrier during the printing process. On the other hand, the refreshing operation is performed by bringing the refreshing member into contact with the latent image carrier as necessary in a state where the printing process is not performed.

  In addition, the image forming method according to the present invention is in contact with the latent image carrier that rotates at a predetermined peripheral speed in a non-contact manner or while rotating at substantially the same peripheral speed as the latent image carrier. And a functional member that acts on the latent image carrier and an intermediate transfer medium that is provided to come into contact with the latent image carrier while rotating at substantially the same peripheral speed as the latent image carrier. In the forming apparatus, the latent image carrier is charged, the latent image is formed on the latent image carrier, the toner is developed on the latent image, and the toner image formed by the toner development is transferred to an intermediate transfer medium for printing. In order to achieve the above-mentioned object, an image forming method for executing processing includes a step of separating the refreshing member from the latent image carrier during the printing process, and a refreshing member as necessary without performing the printing process. Contact with the latent image carrier It is characterized in that a step of refreshing the latent image bearing member to remove the surface layer of the latent image carrier.

  In the invention thus configured (image forming apparatus and method), the refresh member is provided so as to be able to come into contact with and separate from the surface of the latent image carrier. The refresh member is separated from the latent image carrier during the printing process, and the image disturbance due to the refresh member can be reliably prevented and the printing process can be performed satisfactorily. Further, when the printing process is not performed (so-called non-printing state), the refresh member comes into contact with the surface of the latent image carrier as necessary, so that the surface layer portion of the latent image carrier is removed by the refresh member. The carrier is refreshed. As a result, even if the product generated by the charging operation adheres to the surface of the latent image carrier, it is removed by the refresh operation, and as a result, an abnormal image due to the product is prevented and good printing processing is performed. Can be performed.

  Here, the contact timing of the refresh member is arbitrary as long as it is in a non-printing state. For example, (1) after power-on to the apparatus and before the first printing process, (2) termination after the printing process The sequence can be performed at the timing when (3) a product adhering to the surface of the latent image carrier becomes a predetermined amount or more. By employing such timings (1) to (3), the refresh operation can be performed periodically, and the occurrence of abnormal images can be effectively prevented.

  The functional member includes a charging member that charges the latent image carrier, and the amount of the product can be counted based on the driving time of the charging member. Therefore, when the above timing (3) is adopted, timing control based on the driving time of the charging member is desirable. That is, the amount of product generated with the latent image carrier charged and attached to the surface of the latent image carrier is counted based on the driving time of the charging member, and when the count value reaches the refresh request value, the refresh operation is performed. Can be configured to perform. Further, the amount of product may be counted based on the number of printed sheets instead of the driving time of the charging member.

  Also, the occurrence of an abnormal image greatly depends on the surrounding environment of the latent image carrier as described above. Therefore, the surrounding environment of the latent image carrier may be measured by the measuring means, and the refresh operation execution timing may be adjusted based on the measurement result. As a result, for example, in the case of a high humidity environment, the occurrence of an abnormal image can be more reliably prevented by increasing the execution timing of the refresh operation. Further, it is possible to prevent the excessive refresh operation and extend the life of the latent image carrier. In other words, since the surface of the latent image carrier is scraped off by performing the refresh operation, excessive execution of the refresh operation shortens the life of the latent image carrier. However, by optimizing the execution timing of the refresh operation as described above, it is possible to prevent the refresh operation from being performed excessively and extend the life of the latent image carrier.

  In addition, in an image forming apparatus in which an image forming station having a latent image carrier and a functional member is provided for each color along an intermediate transfer medium in order to form a color image, color printing processing and single color printing processing are performed. In some cases, the contact operation between the latent image carrier and the intermediate transfer medium is different. That is, there is known an image forming apparatus that separates a latent image carrier of an image forming station other than the specific color and an intermediate transfer medium from each other during single color printing of the specific color. In this apparatus, each of the plurality of image forming stations is provided with a refresh member and a driving unit, and at the time of monochromatic printing, the refresh member is brought into contact with the latent image carrier at the image forming station other than the specific color. It may be configured to execute. That is, in the image forming station other than the specific color, the monochrome printing process corresponds to the “state in which the printing process is not performed” of the present invention, and therefore, the refresh operation can be performed in parallel with the monochrome printing process. As a result, the refresh operation can be performed efficiently.

  The toner image transferred to the intermediate transfer medium is transferred to the recording material. In the apparatus configured as described above, it is desirable that the peripheral length of the latent image carrier is shorter than the length of the recording material in the rotation direction of the latent image carrier from the viewpoint of miniaturization of the apparatus.

  Further, in order to uniformly refresh the entire surface of the latent image carrier, it is desirable to rotate the latent image carrier one or more times with the refresh member in contact with the surface of the latent image carrier.

<First Embodiment>
FIG. 1 is a diagram showing a first embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus of FIG. The apparatus 1 includes a color printing process for forming a full color image by superposing four color toners (developers) of black (K), cyan (C), magenta (M), and yellow (Y), and black (K ) To selectively execute monochromatic printing processing for forming a monochrome image using only toner. In this image forming apparatus 1, when an image forming command (printing command) is given to the main controller 51 from an external device such as a host computer, the engine controller 52 controls each part of the engine unit EG in accordance with the command from the main controller 51. Then, a predetermined image forming operation is executed, and an image corresponding to the image forming command is formed on a sheet (recording material) S such as copy paper, transfer paper, paper, and an OHP transparent sheet.

  1, an image forming apparatus 1 according to the present embodiment includes a housing body 2, a first opening / closing member 3 that is detachably mounted on the front surface of the housing body 2 (the right-hand side surface in FIG. 1), and the housing body 2. And a second opening / closing member 4 (also serving as a paper discharge tray) mounted on the upper surface so as to be freely opened and closed. The first opening / closing member 3 is provided with an opening / closing lid 3 a that can be opened and closed on the front surface of the housing body 2. The opening / closing lid 3a can be opened / closed in conjunction with or independently of the first opening / closing member 3.

  In the housing main body 2, an electrical component box 5 containing a power circuit board, a main controller 51, and an engine controller 52 is provided. An image forming unit 6, a blower fan 7, a transfer belt unit 9 and a paper feed unit 10 are also disposed in the housing body 2. On the other hand, on the first opening / closing member 3 side, a secondary transfer unit 11, a fixing unit 12 and a sheet conveying mechanism 13 are disposed. In this embodiment, the consumables in the image forming unit 6 and the paper feeding unit 10 are configured to be detachable from the apparatus main body. The consumables and the transfer belt unit 9 can be removed and repaired or exchanged.

  The transfer belt unit 9 is disposed below the housing body 2 and is driven to rotate by a drive motor (not shown), a driven roller 15 disposed obliquely above the drive roller 14, and the two rollers. An intermediate transfer belt 16 that is stretched between 14 and 15 and is circulated and driven in the direction of the arrow D16 in the figure, and a cleaning unit 17 that contacts the surface of the intermediate transfer belt 16 are provided. The driven roller 15 is disposed obliquely above the drive roller 14 (upward on the left hand in FIG. 1). For this reason, the intermediate transfer belt 16 rotates and moves in the direction D16 while being inclined. Further, the belt surface 16a in which the belt conveyance direction D16 when the intermediate transfer belt 16 is driven is downward (right downward in FIG. 1) is positioned below. In the present embodiment, the belt surface 16a is a belt tension surface (surface pulled by the drive roller 14) when the belt is driven, and substantially the same peripheral speed (for example, the peripheral speed of each color latent image carrier described later) About 103%).

  The driving roller 14 and the driven roller 15 are rotatably supported by the support frame 9a. A rotation portion 9b is formed at the lower end of the support frame 9a and is fitted to a rotation shaft (rotation fulcrum) 2b provided on the housing body 2. As a result, the support frame 9 a is rotatable with respect to the housing body 2. On the other hand, a lock lever 9c is rotatably provided at the upper end of the support frame 9a and can be locked to a locking shaft 2c provided in the housing body 2.

The drive roller 14 also serves as a backup roller for the secondary transfer roller 19 constituting the secondary transfer unit 11. As shown in FIG. 1, a rubber layer 14a having a thickness of about 3 mm and a volume resistivity of 10 ⁵ Ω · cm or less is formed on the peripheral surface of the drive roller 14 and is grounded through a metal shaft. Thus, a conductive path for the secondary transfer bias supplied from the secondary transfer bias generator (not shown) via the secondary transfer roller 19 is provided. Thus, by providing the driving roller 14 with the rubber layer 14a having high friction and shock absorption, it is difficult for the impact when the sheet S enters the secondary transfer portion to be transmitted to the intermediate transfer belt 16, and the image quality is deteriorated. Can be prevented.

  In the present embodiment, the diameter of the driving roller 14 is smaller than the diameter of the driven roller 15. Thereby, the sheet S after the secondary transfer can be easily peeled by the elastic force of the sheet S itself. Further, the driven roller 15 is also used as a backup roller for the cleaning unit 17. The cleaning unit 17 is provided on the side of the belt surface 16a facing downward in the transport direction, and includes a cleaning blade 17a that removes residual toner and a toner transport member that transports the removed toner, as shown in FIG. Yes. The cleaning blade 17a contacts the intermediate transfer belt 16 at a portion where the intermediate transfer belt 16 is wound around the driven roller 15, and cleans and removes toner remaining on the surface of the intermediate transfer belt 16 after the secondary transfer.

  A primary transfer roller 21a is disposed on the back surface of the belt surface 16a facing downward in the transport direction of the intermediate transfer belt 16 so as to face a latent image carrier 20 of each image forming station Y, M, C, K described later. A primary transfer unit 21 is provided. In the primary transfer unit 21, four primary transfer rollers 21a are rotatably supported with respect to the link bar 21b. These primary transfer rollers 21a are electrically connected to a primary transfer bias generator (not shown), and a primary transfer bias is applied from the primary transfer bias generator at an appropriate timing.

  The link bar 21b is rotatably provided in the arrow direction D21 with the primary transfer roller 21a disposed facing the latent image carrier 20 of the black (K) image forming station K as a rotation center. Yes. Then, by actuating an actuator (not shown), the link bar 21b rotates to move to the latent image carrier 20 of the yellow (Y), magenta (M), and cyan (C) image forming stations Y, M, and C. The primary transfer roller 21 a disposed so as to be close to the latent image carrier 20 moves away from the latent image carrier 20. For this reason, when each primary transfer roller 21a moves close to the latent image carrier 20, it comes into contact with the latent image carrier 20 with the intermediate transfer belt 16 in between (solid line in FIG. 1). Conversely, when each primary transfer roller 21a moves away from the latent image carrier 20, the latent image carrier 20 and the intermediate transfer belt 16 of the image forming stations Y, M, and C are separated from each other (broken line in FIG. 1). ). On the other hand, the primary transfer roller 21a disposed facing the latent image carrier 20 of the black (K) image forming station K is in contact with the latent image carrier 20 with the intermediate transfer belt 16 interposed therebetween. It is configured to rotate as it is. Therefore, as shown by the solid line in FIG. 1, the color printing process can be executed by positioning all the primary transfer rollers 21a on the latent image carrier 20 side. On the other hand, as shown by the broken line in the figure, the black primary transfer roller 21a is left and the other primary transfer roller 21a is separated from the latent image carrier 20, thereby performing image formation while performing only monochrome printing processing. Stations Y, M, and C can be set in a non-printing state.

  A test pattern sensor 18 is installed on the support frame 9 a of the transfer belt unit 9 in the vicinity of the drive roller 14. This test pattern sensor 18 is a sensor for positioning each color toner image on the intermediate transfer belt 16, detecting the density of each color toner image, and correcting the color shift and image density of each color image. In this embodiment, in addition to the sensor 18, a vertical synchronization sensor 60 (FIG. 2) that detects a characteristic part of the intermediate transfer belt 16 (for example, a protrusion protruding in the width direction) is attached to the support frame 9 a. It has been. For this reason, a vertical synchronization signal (reference signal) is output every time the characteristic portion of the intermediate transfer belt 16 passes the sensor 60.

  The image forming unit 6 includes image forming stations Y (for yellow), M (for magenta), C (for cyan), and K (for black) that form a plurality (four in this embodiment) of different color images. I have. Each of the image forming stations Y, M, C, and K is provided with a latent image carrier 20 including a photosensitive drum. Further, around each latent image carrier 20, a charging member 22, an image writing member 23, a developing unit 24, and a refresh blade 251 of a refresh unit 25 are disposed. In this embodiment, the charging member 22, the image writing member 23, and the developing roller 33 of the developing unit 24 correspond to the “functional member” of the present invention. An image forming operation and a toner developing operation are executed. Note that the developing unit 24 attaches a reference numeral only to the image forming station K and omits the reference numerals because the other image forming stations have the same configuration. Further, the arrangement order of the image forming stations Y, M, C, and K is arbitrary.

  Then, the latent image carrier 20 of each of the image forming stations Y, M, C, and K is brought into contact with the belt surface 16a facing downward in the transport direction of the intermediate transfer belt 16, and as a result, each of the image forming stations Y, M, C, and K are also arranged in a direction inclined to the left in the drawing with respect to the drive roller 14. Each latent image carrier 20 is rotationally driven at a predetermined peripheral speed in the conveyance direction of the intermediate transfer belt 16 as indicated by an arrow D20 in the drawing. In this embodiment, in the rotation direction D20 of the latent image carrier 20, the peripheral length of the latent image carrier 20 is shorter than the minimum sheet length, for example, a postcard size.

The charging member 22 is composed of a conductive brush roller connected to a charging bias generator (not shown), rotates in the same direction as the latent image carrier 20 that is a photosensitive member, and is applied at substantially the same peripheral speed. The surface of the latent image carrier 20 is uniformly charged by contact rotation. The conductive brush roller is a square inch of semiconductive fibers having a thickness of 2 to 6 denier and a yarn resistance of 10 ⁷ to 10 ⁹ Ω on the surface of a highly conductive shaft member (for example, a metal shaft) having a diameter of 5 to 8 mm. 150,000 to 430,000 pile-woven fabrics are wound in a spiral shape, and are held rotatably so that the contact depth with respect to the latent image carrier 20 is 0.3 to 0.5 mm. The configuration of the charging member 22 is not limited to this, and a conventionally known charging method, for example, a non-contact charging method such as scorotron charging, or a charging roller at a substantially same peripheral speed as the latent image carrier 20. A roller charging method in which the toner is charged while being rotated may be used.

  When a negatively chargeable photoconductor is used as the latent image carrier 20, the voltage applied to the brush roller is a voltage obtained by superimposing an AC component having a frequency of about 1 KHz on a DC component -300 to -500 V and 800 to 1300 V. It is desirable. In addition, when an image forming method having a cleaner-less configuration is used as in the present embodiment, the transfer residual toner attached to the brush roller by applying a bias having a polarity opposite to the charging polarity of the toner to the brush roller during the non-printing process. It is desirable that the toner is discharged to the latent image carrier 20, transferred onto the intermediate transfer belt 16 at the primary transfer portion, and collected by the cleaning portion 17 of the intermediate transfer belt 16.

  The image writing member 23 uses an array-like writing head in which elements such as a liquid crystal shutter having a light emitting diode and a backlight are arranged in a line in the axial direction of the latent image carrier 20. Spaced apart from each other. The array-like writing head has an advantage that the optical path length is shorter than that of the laser scanning optical system, is compact, can be arranged close to the latent image carrier 20, and the entire apparatus can be downsized. In this embodiment, the latent image carrier 20, the charging member 22, and the image writing member 23 of each image forming station Y, M, C, K are unitized as replacement cartridges 6Y, 6M, 6C, 6K (FIG. 2). By doing so, the arrangement of the arrayed write head is maintained, and when replacing the replacement cartridge, the arrayed write head is replaced and the new replacement cartridge is adjusted for light quantity and positioned for reuse. It is configured to do. Each replacement cartridge 6Y, 6M, 6C, 6K is provided with non-volatile memories 91-94 for storing information relating to the replacement cartridge. The transmission / reception units 53Y, 53M, 53C, and 54K provided in each replacement cartridge and the transmission / reception units 522Y, 522M, 522C, and 522K provided on the main body side are arranged close to each other, and the CPU 521 and the memory of the engine controller 52 are arranged. Wireless communication is performed with 91-94. In this way, information regarding each replacement cartridge is transmitted to the CPU 521, and information in each of the memories 91 to 94 is updated and stored.

  Next, details of the developing unit 24 will be described on behalf of the image forming station K. In the present embodiment, the image forming stations Y, M, C, and K are disposed in an oblique direction, and the latent image carrier 20 is in contact with the belt surface 16 a facing downward in the conveyance direction of the intermediate transfer belt 16. Above, the toner storage container 26 is disposed obliquely downward. Therefore, a special configuration is adopted as the developing unit 24. That is, the developing unit 24 is disposed in the toner storage container 26 that stores toner (hatched portion in FIG. 1), the toner storage part 27 formed in the toner storage container 26, and the toner storage part 27. The toner agitating member 29, the partition member 30 formed in the upper part of the toner reservoir 27, the toner supply roller 31 disposed above the partition member 30, and the toner supply roller 31 provided in the partition member 30 A blade 32 in contact, a developing roller 33 that contacts the toner supply roller 31 and the latent image carrier 20 and rotates at substantially the same peripheral speed as the latent image carrier 20, and a regulating blade that contacts the developing roller 33 34. In this embodiment, a contact development method is employed, but a non-contact development method can be employed.

  The latent image carrier 20 is rotated in the transport direction D16 of the intermediate transfer belt 16. Further, the developing roller 33 and the supply roller 31 are rotationally driven in a direction opposite to the rotational direction D20 of the latent image carrier 20 as indicated by an arrow D33 in the drawing. On the other hand, the stirring member 29 is driven to rotate in the direction opposite to the rotation direction of the supply roller 31. Therefore, the toner stirred and carried by the stirring member 29 in the toner reservoir 27 is supplied to the toner supply roller 31 along the upper surface of the partition member 30. In addition, the toner thus supplied is rubbed against the blade 32 and supplied to the surface of the developing roller 33 by the mechanical adhesion force on the surface uneven portion of the supply roller 31 and the adhesion force due to the frictional band power. The toner supplied to the developing roller 33 is regulated to a predetermined thickness by the regulation blade 34. Further, the toner layer thus thinned is conveyed to the latent image carrier 20 and the latent image carrier 20 is in the vicinity of the nip portion where the developing roller 33 and the latent image carrier 20 are in contact with each other. Develop the image area.

  In the case of using the cleaner-less image forming method as in the present embodiment, spherical toner is increasingly used from the viewpoint of improving transfer efficiency, and the cleaner-less image forming technique is practically used. In order to pull it up, it is desirable to use toner having a sphericity of 0.96 or more. Here, the average sphericity of the toner can be measured by using, for example, a flow type particle image analyzer FPIA-2100 (manufactured by Sysmex Corporation). In this apparatus, a flat sheath flow cell and a CCD camera and a strobe are arranged at positions facing each other across the cell. Then, the toner particles dispersed in water or the like are sucked to pass through the flat sheath flow cell, and the passing particles are photographed in a state where the strobe is flashed. The obtained image is computer processed to measure the area of each particle (particle projected area) and the perimeter of the projected particle image, and to calculate the spherical equivalent diameter of each particle by calculating the equivalent circle diameter of the particle with a computer. Can be sought.

  Next, the refresh unit 25 will be described in detail with reference to FIG. As a characteristic configuration of this embodiment, a refresh blade 251 of the refresh unit 25 is provided between the developing position and the primary transfer position so as to be able to come into contact with and separate from the surface of the latent image carrier 20.

  FIG. 3 is a diagram showing a configuration of a refresh unit that performs a refresh process on the latent image carrier. In the refresh unit 25, the refresh blade 251 is disposed so as to be able to come into contact with the latent image carrier 20 at the refresh position Prf. That is, the upper end portion of the refresh blade 251 is connected to the rear end portion of the swing lever 252 and the connecting portion is fixed to the rotating shaft 253 so that the refresh blade 251 and the swing lever 252 rotate integrally. It is freely rotatable around the moving shaft 253. By this turning operation, the tip of the refresh blade 251 moves and contacts the latent image carrier 20 (FIG. 1A), or the tip of the refresh blade 251 moves away from the latent image carrier 20 and is separated. ((B) in the figure). In this embodiment, a spring member 254 is attached to the lower end portion of the swing lever 252, and the refresh blade 251 is brought into contact with the latent image carrier 20 by the biasing force of the spring member 254.

  A blade driving mechanism 255 is provided to drive the refresh blade 251 to come into contact with the latent image carrier 20. The blade driving mechanism 255 includes a rotating shaft 256 and an eccentric cam 257 that is fixed to the rotating shaft 256 and causes the refresh blade 251 to come into contact with and separate from the latent image carrier 20. The rotating shaft 256 is connected to the driving motor 259 via the clutch 258. When the clutch 258 is closed by a command from the engine controller 52, the driving force of the driving motor 259 is transmitted to the rotating shaft 256, and the cam 257 Rotates.

  Here, the eccentric cam 257 is fixed to the rotary shaft 256 so that the refresh blade 251 is selectively rotated and positioned at one of two positions as shown in FIG. That is, FIG. 6A shows a state in which the refresh blade 251 is in contact with the latent image carrier 20, and the cam 257 is separated from the swing lever 252 of the refresh blade 251 (hereinafter, “ Contact position ”). FIG. 5B shows a state where the refresh blade 251 is separated from the latent image carrier 20, and the cam 257 is in contact with the swing lever 252 of the refresh blade 251 (hereinafter, “ "Separated position").

Then, the blade initialization operation and the refresh operation are selectively performed as necessary. The outline of “blade initialization operation” and “refresh operation” is as follows:
Blade initialization operation: An operation in which the refresh blade 251 is first forcibly moved and brought into contact with the surface of the latent image carrier 20, and further moved away from the surface to position the refresh blade 251 at a separated position (initial position);
Refresh operation: An operation for refreshing the latent image carrier 20 by scraping the surface layer of the latent image carrier 20 by bringing the refresh blade 251 into contact with the latent image carrier 20.

  Returning to FIG. 1, the description of the device configuration will be continued. The sheet feeding unit 10 includes a sheet feeding unit including a sheet feeding cassette 35 in which sheets S are stacked and held, and a pickup roller 36 that feeds the sheets S from the sheet feeding cassette 35 one by one. In the first opening / closing member 3, a registration roller pair 37 that regulates the sheet feeding timing of the sheet S to the secondary transfer portion, and a secondary transfer unit 2 that is in pressure contact with the drive roller 14 and the intermediate transfer belt 16. A next transfer unit 11, a fixing unit 12, a sheet conveyance mechanism 13, a paper discharge roller pair 39, and a duplex printing conveyance path 40 are provided.

  In the secondary transfer unit 11, the secondary transfer roller 19 is provided so as to be able to come into contact with and separate from the intermediate transfer belt 16, and a secondary transfer roller drive mechanism 111 that drives the secondary transfer roller 19 to come into contact with and separate from the intermediate transfer belt 16. ing. Note that the secondary transfer roller driving mechanism 111 basically has the same configuration as the blade driving mechanism 255. That is, a rotating lever 42 having a secondary transfer roller 19 rotatably attached to one end thereof is pivotally supported on the fixed shaft 41. Further, a spring 43 is disposed between the other end of the rotation lever 42 and the first opening / closing member 3, and the secondary transfer roller 19 moves in the direction of the arrow in the drawing by the biasing force, and the intermediate transfer belt. 16 and the driving roller 14. Further, the secondary transfer roller driving mechanism 111 has an eccentric cam 44, and this eccentric cam 44 is provided on the spring 43 side of the rotating lever 42. When the eccentric cam is rotated by the driving force of the drive motor via a clutch (not shown), the rotation lever 42 rotates against the spring 43 to separate the secondary transfer roller 19 from the intermediate transfer belt 16. .

  The fixing unit 12 includes a heating roller 45 that includes a heating element such as a halogen heater and is rotatable, a pressure roller 46 that presses and biases the heating roller 45, and is swingable on the pressure roller 46. A belt tension member 47, and a heat-resistant belt 49 stretched between the pressure roller 46 and the belt tension member 47. The image secondarily transferred to the sheet S is fixed to the sheet S at a predetermined temperature at a nip formed by the heating roller 45 and the heat-resistant belt 49. In the present embodiment, the fixing unit 12 can be disposed in a space formed obliquely above the intermediate transfer belt 16, in other words, in a space opposite to the image forming unit 6 with respect to the intermediate transfer belt 16. Thus, heat transfer to the electrical component box 5, the image forming unit 6, and the intermediate transfer belt 16 can be reduced, and the frequency of performing the color misregistration correction operation for each color can be reduced.

  Further, the sheet S thus subjected to the fixing process is conveyed to a second opening / closing member (discharge tray) 4 provided on the upper surface portion of the apparatus main body via the discharge roller pair 39. Further, when images are formed on both sides of the sheet S, when the rear end portion of the sheet S on which the image is formed on one side as described above is conveyed to the reverse position behind the pair of discharge rollers 39. The rotation direction of the discharge roller pair 39 is reversed, whereby the sheet S is conveyed along the duplex printing conveyance path 40. Then, it is put on the conveyance path again before the registration roller pair 37. At this time, the image is transferred first on the surface of the sheet S on which the image is transferred in contact with the intermediate transfer belt 16 in the secondary transfer region. It is the opposite surface. In this way, images can be formed on both sides of the sheet S.

  In addition, as shown in FIG. 2, the apparatus 1 includes a display unit 54 that is controlled by the CPU 511 of the main controller 51. The display unit 54 is configured by, for example, a liquid crystal display, and in accordance with a control command from the CPU 511, the operation guidance to the user, the progress of the image forming operation, the occurrence of an abnormality in the apparatus, the replacement timing of any unit, and the like A predetermined message for notification is displayed.

  In FIG. 2, reference numeral 513 denotes an image memory provided in the main controller 51 for storing an image given from an external device such as a host computer via the interface 512. Reference numeral 523 denotes a ROM for storing a calculation program executed by the CPU 521, control data for controlling the engine unit EG, and the like. Reference numeral 524 denotes a RAM for temporarily storing calculation results in the CPU 521 and other data. is there.

  Next, a refresh operation in the image forming apparatus configured as described above will be described with reference to FIGS. FIG. 4 is a timing chart showing the operation when the power is turned on in the image forming apparatus of FIG. FIG. 5 is a diagram schematically showing the operation of the refresh member when the power is turned on.

  When the apparatus of FIG. 1 is turned on, the refresh process for the latent image carrier 20 is executed as follows before the first printing process. That is, when a predetermined time elapses after the power is turned on, the engine controller EG controls each part of the engine unit EG as follows to execute sheet conveyance preparation, blade initialization operation, refresh operation, and normal printing sequence. First, preparation for sheet conveyance is executed, and the driving roller 14 is rotationally driven by a driving motor disposed below the housing body 2 to start rotational driving of the intermediate transfer belt 16. Then, each time the characteristic part of the intermediate transfer belt 16 passes the vertical synchronization sensor 60, the vertical synchronization signal (reference signal) Vsync is output. That is, the vertical synchronization signal Vsync is output every time the intermediate transfer belt 16 makes one round, and the cycle corresponds to one round of the intermediate transfer belt 16. In this embodiment, the operation of a static eliminator (eraser) (not shown) is started, and the static eliminating process is performed on the surface of the latent image carrier 20. This static elimination process is continued until the blade initialization operation and the refresh operation described below are completed.

  In this blade initialization operation, driving of the drive motor 259 is started in accordance with a drive command from the engine controller 52. At the same time or slightly later, the clutch 258 is closed and the rotational drive from the drive motor 259 is transmitted to the rotary shaft 256. As a result, the rotating shaft 256 rotates and the refresh blade 251 is brought into contact with and separated from the latent image carrier 20. That is, as indicated by a one-dot chain line in FIG. 5A, the refresh blade 251 is forcibly moved and brought into contact with the surface of the latent image carrier 20. Thereafter, the cam 257 is stopped at a predetermined angle by the clutch 258. As a result, the refresh blade 251 is positioned at the initial position (home position) as indicated by the solid line in FIG. Note that the symbol DP in the figure indicates a product such as nitric acid or nitrate that is generated along with the charging operation and adheres to the surface of the latent image carrier 20.

  Thus, when the blade initialization operation is completed, the application of the charging bias to the charging member is started and the refresh operation is started after the first vertical synchronization signal Vsync is output. That is, the clutch 258 is closed in response to the contact command from the engine controller 52, and the rotational drive from the drive motor 259 is transmitted to the rotary shaft 256 to move the refresh blade 251 to the latent image carrier 20 (see FIG. (B)). Then, by maintaining the contact state of the refresh blade 251 with the latent image carrier 20, the surface layer portion of the latent image carrier 20 is scraped off, and the product DP attached to the latent image carrier 20 is removed. . In this way, the refresh process of the latent image carrier 20 is executed. Here, the latent image carrier 20 is rotated while the refresh blade 251 is in contact with the surface of the latent image carrier 20 for a time T longer than the period of the vertical synchronization signal Vsync. That is, the refresh operation is completed after the latent image carrier 20 is rotated one or more times in a state where the refresh blade 251 is in contact with the surface of the latent image carrier 20 ((c) in the figure). As a result, the entire surface of the latent image carrier 20 can be refreshed uniformly.

  When the refresh process (blade initialization process + refresh operation) is completed in this way, the clutch 258 is closed in response to the separation command from the engine controller 52, and the rotational drive from the drive motor 259 is transmitted to the rotary shaft 256 to refresh the refresh blade 251. Is positioned away from the latent image carrier 20 and stopped at the home position. Further, after detecting the output of the next vertical synchronizing signal Vsync, the rotation of the latent image carrier 20 is stopped and the eraser is turned off to wait for the input of an image forming command.

  When an image forming command (printing command) is given to the main controller 51 from an external device such as a host computer, a normal printing sequence is executed to execute printing processing. Note that after the refresh process is performed immediately after the power is turned on, the refresh blade 251 stands by at the home position, and the image disturbance caused by the refresh blade 251 can be reliably prevented and the print process can be performed satisfactorily. it can.

  As described above, in this embodiment, since the refresh process is executed immediately after the power is turned on, the product (such as nitric acid or nitrate) adhered to the surface of the latent image carrier 20 during the previous apparatus operation period. ) It is possible to execute the printing process using the latent image carrier 20 in a fresh state with the DP removed reliably. As a result, it is possible to prevent an abnormal image from being generated by the product DP and perform a good printing process. Although the refresh process is executed here when the power is turned on, the refresh operation may be executed during the end sequence after the print process. Of course, the refresh operation may be executed both at power-on and at the end sequence.

Second Embodiment
In the first embodiment described above, the contact timing of the refresh blade 251 to the latent image carrier 20 is (1) after the power is turned on to the apparatus and before the first printing process, and (2) the end sequence after the printing process. The time is arbitrary as long as it is in the non-printing state. For example, one of the generation factors of the product is ozone generation accompanying the charging operation. That is, the amount of the product adhering to the surface of the latent image carrier 20 increases in proportion to the cumulative charging time, and as a result, the probability of occurrence of an abnormal image increases. Therefore, in the second embodiment, the refresh process is executed when the product adhering to the surface of the latent image carrier 20 becomes a predetermined amount or more. Hereinafter, the second embodiment will be described in detail with reference to FIGS. 6 and 7.

  FIG. 6 is a flowchart showing the operation of the image forming apparatus according to the second embodiment. FIG. 7 is a schematic diagram showing the operation of the image forming apparatus according to the second embodiment. In the second embodiment, the execution timing of the refresh process is individually controlled in each of the image forming stations Y, M, C, and K. That is, the amount of products generated in the nonvolatile memories 91 to 94 attached to the replacement cartridges 6Y, 6M, 6C, and 6K as the latent image carrier 20 is charged and attached to the surface of the latent image carrier 20 A count value CT is stored as an index value indicating. The count value CT is read from each of the memories 91 to 94 and stored in the RAM 524 at an appropriate timing, for example, when the power is turned on or the cartridge is replaced (step S1).

  Then, the engine controller 52 executes steps S2 to S8 for each color and periodically executes the refresh process. First, when it is detected in step S2 that the charging drive has been executed, a count value CT (cg) corresponding to the drive time required for the charging is calculated (step S3). The count value CT (cg) indicates the amount of products such as nitric acid and nitrate newly generated during the charging operation. Further, the count value CT (cg) thus obtained is added to the original count value CT (step S4). As a result, the total amount of products attached to the surface of the latent image carrier 20 can be obtained. Further, in this embodiment, since the count value CT is obtained for each color, it is possible to accurately grasp the adhesion state of the product of each latent image carrier 20, and as a result, the start timing of the refresh process Can be controlled individually. For example, when only monochrome printing processing is performed continuously, only the black count value CT increases, whereas when performing color printing processing, the count value CT of each color increases in parallel. The correlation between the charging drive time and the count value CT (cg) can be obtained in advance through experiments or the like and stored in the ROM 523 in a table format or a function format.

  In the next step S5, the count value CT obtained as described above is compared with the refresh request value CTrf. Here, the “refresh request value CTrf” means a reference value indicating that a product such as nitric acid has adhered to the surface of the latent image carrier 20 up to the limit of occurrence of an abnormal image. Therefore, when the count value CT becomes equal to or greater than the refresh request value CTrf, an abnormal image may occur. Therefore, in this embodiment, the count value CT is less than the refresh request value CTrf, and as shown in FIG. 7A, it is determined that the refresh process is unnecessary while the amount of the product DP attached is relatively small. And continue normal printing.

  On the other hand, when the count value CT is equal to or greater than the refresh request value CTrf, it is determined that the refresh process is necessary. In this case, the refresh process is executed after waiting for the apparatus 1 to shift from the print process state to the non-print process state in step S6 (step S7). The specific content of this refresh process is the same as that of the first embodiment. That is, as shown in FIG. 5B, after executing the blade initialization operation, the application of the charging bias to the charging member is started after the vertical synchronization signal Vsync is output, and the refresh operation is performed. Start. In this refresh operation, the refresh blade 251 is moved and brought into contact with the latent image carrier 20 in accordance with a contact command from the engine controller 52 ((c) in the figure). Then, the latent image carrier 20 is rotated one or more times while maintaining the contact state of the refresh blade 251 with the latent image carrier 20. Thus, as shown in FIG. 4D, the surface layer portion of the latent image carrier 20 is scraped off, and the product DP is removed from the latent image carrier 20.

  When the refresh process (blade initialization operation + refresh operation) is completed in this way, the count value CT is cleared in step S8, and then the process returns to step S2 to repeat the normal printing operation (steps S2 to S7). )repeat. Thereby, the start timing of the refresh process can be optimized.

  As described above, according to this embodiment, since the start timing of the refresh process is controlled based on the count value CT, the product DP exceeding the abnormal image generation start limit adheres to the surface of the latent image carrier 20. The refresh process can be started immediately before the start. Therefore, the refresh process can be performed at an effective timing. As a result, the following effects can be obtained. That is, it is possible to prevent the refresh process from being started at a stage where the amount of the product DP attached is small and improve the operating rate of the apparatus. Further, excessive refresh processing can be prevented to prevent the surface of the latent image carrier 20 from being damaged, and the replacement life of the latent image carrier 20 can be extended.

  In addition, the count value CT corresponding to each replacement cartridge 6Y, 6M, 6C, 6K is stored by writing the count value CT in the memories 91 to 94 at an appropriate timing, for example, when the cartridge is replaced or when a certain time elapses. Can be made. Thereby, the amount of the product DP adhering to each latent image carrier 20 can be periodically updated. Then, the count value CT is read from the memory of each replacement cartridge 6Y, 6M, 6C, 6K (step S1), thereby the product DP adhering to the latent image carrier 20 of each replacement cartridge 6Y, 6M, 6C, 6K. Can be accurately determined. In particular, when the replacement cartridge taken out from the apparatus main body during use is attached to the apparatus main body again or attached to another apparatus main body, the newly attached replacement cartridge adheres to the latent image carrier 20 The amount of the object DP can be obtained, and the start timing of the refresh process can be optimized. As a result, the occurrence of an abnormal image can be effectively prevented even in an apparatus that replaces and uses a cartridge including the latent image carrier 20.

  In the second embodiment, the amount of the product DP adhering to the surface of the latent image carrier 20 is obtained based on the charging drive time. However, for the amount of the product DP, other index values, for example, the number of printed sheets Alternatively, it may be determined based on the device operating time or the like.

<Third Embodiment>
By the way, the occurrence of an abnormal image greatly depends on the surrounding environment of the latent image carrier 20 as described in the section “Problems to be Solved by the Invention”. Therefore, it is desirable to optimize the start timing of the refresh process in consideration of the surrounding environment of the latent image carrier 20, particularly humidity and temperature. Hereinafter, the third embodiment of the present invention will be described in detail with reference to FIGS. 8 and 9.

  FIG. 8 is a flowchart showing the operation of the image forming apparatus according to the third embodiment. FIG. 9 is a diagram showing optimum refresh request values based on humidity and temperature. In the third embodiment, a humidity sensor and a temperature sensor are arranged in the housing body 2 in order to measure the surrounding environment of the latent image carrier 20. Then, measurement results (temperature information and humidity information) by these sensors are input to the CPU 521 of the engine controller 52 (steps S11 and S12). Upon receiving the humidity and temperature information, the CPU 521 obtains a refresh request value CTrf suitable for the surrounding environment based on the data table of FIG. More specifically, a value CT (th) corresponding to the intersection of temperature information and humidity information is read from the table of FIG. 9 (step S13). Then, the refresh request value CTrf is rewritten with this value CT (th) as a new refresh request value (step S14).

  Then, the count value CT is calculated in the same manner as in the second embodiment, and the refresh process is executed when the count value CT becomes equal to or greater than the refresh request value CTrf rewritten as described above. Thereby, the execution timing of the refresh process is adjusted to the timing corresponding to the surrounding environment of the latent image carrier 20.

  As described above, in this embodiment, the humidity and temperature around the latent image carrier 20 are measured by the sensor (measurement means), and the execution timing of the refresh process is adjusted based on the measurement result. Such effects can be obtained. For example, in a high humidity environment, the refresh request value CTrf is rewritten to a relatively small value as is apparent from the table value of FIG. 9, and the execution timing of the refresh process is advanced. This can more reliably prevent the occurrence of abnormal images. As the humidity decreases, the refresh request value CTrf is rewritten to a relatively large value, and the execution timing of the refresh process is delayed. As a result, excessive refresh processing can be prevented and the life of the latent image carrier 20 can be extended.

  In the third embodiment, the refresh request value CTrf is rewritten based on the information about the two surrounding environments, temperature information and humidity information. However, preferably, the refresh request value CTrf is preferably rewritten using only the humidity information. You may do it. Further, the execution / non-execution of the refresh process in the end sequence immediately after power-on or after the print process may be controlled based on information on the surrounding environment.

<Fourth embodiment>
Further, in the image forming apparatus of FIG. 1, the link bar 21b is rotatable about the primary transfer roller 21a disposed opposite to the latent image carrier 20 of the black (K) image forming station K. The primary transfer roller 21a disposed opposite to the latent image carrier 20 of the yellow (Y), magenta (M), and cyan (C) image forming stations Y, M, and C by the rotating operation. Moves away from and contacts the latent image carrier 20. That is, in the color printing process, the primary transfer rollers 21a for yellow (Y), magenta (M), and cyan (C) all move close to the latent image carrier 20 and sandwich the intermediate transfer belt 16 therebetween. It abuts on the latent image carrier 20 (solid line in FIG. 1).

  Conversely, in the single color printing process, all of these primary transfer rollers 21a move away from the latent image carrier 20, and the latent image carrier 20 and the intermediate transfer belt 16 of the image forming stations Y, M, and C are separated. They are separated from each other (broken line in FIG. 1). Therefore, in the monochrome printing process, as shown in the left column of FIG. 10, a toner image TI (K) is formed on the latent image carrier 20 of the black (K) image forming station K. Further, the black primary transfer roller 21a disposed to face the latent image carrier 20 rotates while being in contact with the latent image carrier 20 with the intermediate transfer belt 16 interposed therebetween, thereby rotating the toner image TI ( K) is transferred to the intermediate transfer belt 16. However, for colors other than black, as shown in the right column of the figure, the primary transfer roller 21a is separated from the latent image carrier 20, and the image forming stations Y, M, and C are in a non-printing state. Yes. That is, the image forming stations Y, M, and C other than the black color at the time of monochromatic printing correspond to the “state in which the printing process is not performed” of the present invention, and thus the refresh process is performed in parallel with the monochromatic printing process. It can be performed. Therefore, in the fourth embodiment, during monochrome printing, the refresh blade 251 of the image forming stations Y, M, and C other than the black color is brought into contact with the latent image carrier 20 to execute the refresh process. As a result, the refresh process can be performed efficiently.

  In the fourth embodiment, the monochrome printing process is executed with the black color as the “specific color” of the present invention. However, the application target of the present invention is not limited to this, and the present invention can also be applied to an apparatus that performs single color printing using other toner colors as specific colors. And the effect similar to the above is obtained.

<Others>
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the blade driving mechanism 255 using a cam is used as the “driving means” of the present invention, but the separation contact driving method of the refresh blade 251 with respect to the latent image carrier 20 is arbitrary. Further, it is arbitrary whether to directly control the drive of the refresh blade 251 by directly detecting the position of the refresh blade 251 or to control the drive of the refresh blade 251 by so-called open loop control. Accordingly, when the initialization operation of the refresh blade 251 is unnecessary, the refresh operation can be immediately executed without performing the blade initialization operation in the refresh process.

  In addition, the present invention is applied to an image forming apparatus using the intermediate transfer belt 16 as an intermediate transfer medium. However, the toner image on the image forming apparatus using the intermediate transfer medium such as an intermediate transfer drum or the latent image carrier 20 is used. The present invention can also be applied to an image forming apparatus that directly transfers the image to the sheet S. Further, the blade 251 is used as the refresh member, but any member that can abut the surface of the latent image carrier 20 and remove the surface layer portion of the latent image carrier 20 to refresh the latent image carrier 20 can be used. The shape, size, number, etc. are arbitrary. Further, the arrangement position of the refresh member is not limited to between the development position and the primary transfer position, and can be provided at any position along the surface of the latent image carrier.

  In each of the above embodiments, the present invention is applied to an apparatus that forms an image using toners of four colors, yellow, magenta, cyan, and black. However, the types and number of toner colors are limited to those described above. It is optional. Furthermore, the present invention can be applied not only to a tandem type image forming apparatus but also to a so-called rotary development type apparatus.

1 is a diagram illustrating a first embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus in FIG. 1. The figure which shows the structure of a refresh part. 6 is a timing chart showing an operation when power is turned on in the image forming apparatus. The figure which shows typically operation | movement of the refresh member at the time of power activation. 9 is a flowchart showing the operation of the image forming apparatus according to the second embodiment. FIG. 9 is a schematic diagram illustrating an operation of an image forming apparatus according to a second embodiment. 10 is a flowchart showing the operation of the image forming apparatus according to the third embodiment. The figure which shows the optimal refresh request value based on humidity and temperature. FIG. 10 is a schematic diagram illustrating an operation of an image forming apparatus according to a fourth embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 16 ... Intermediate transfer belt (intermediate transfer medium), 20 ... Latent image carrier, 22 ... Charging member (functional member), 23 ... Image writing member (functional member), 24 ... Developing part (function) Member), 52 ... engine controller (control means), 251 ... refresh blade (refresh member), 255 ... blade drive mechanism (drive means), 521 ... CPU (control means), DP ... product, S ... sheet (recording material) )

Claims (13)

A latent image carrier that rotates at a predetermined peripheral speed and the latent image carrier that is provided in contact with the latent image carrier in a non-contact manner or while rotating at substantially the same peripheral speed as the latent image carrier. A functional member acting on the body, and an intermediate transfer medium provided to come into contact with the latent image carrier while rotating at substantially the same peripheral speed as the latent image carrier, and charging the latent image carrier In an image forming apparatus that performs a printing process by forming a latent image on the latent image carrier, developing the toner of the latent image, and transferring a toner image formed by the toner development onto the intermediate transfer medium. ,
A refresh that is provided so as to be able to come into contact with and separate from the surface of the latent image carrier, removes the surface layer portion of the latent image carrier, and refreshes the latent image carrier by contacting the surface of the latent image carrier. Members,
Driving means for driving the refreshing member apart and abutting;
Control means for giving a drive command to the drive means to control the separation / contact operation of the refresh member,
The control means separates the refresh member from the latent image carrier during the printing process, while bringing the refresh member into contact with the latent image carrier as necessary without performing the printing process. An image forming apparatus that performs a refresh operation. The image forming apparatus according to claim 1, wherein the printing process is executed in response to a printing command given to the apparatus.
The control unit is an image forming apparatus that executes the refresh operation after powering on the apparatus and before the first printing process. The image forming apparatus according to claim 1, wherein a predetermined end sequence is executed after the printing process is executed in response to a printing command given to the apparatus.
The image forming apparatus that performs the refresh operation in the end sequence.   The control means counts the amount of a product that is generated along with the charging of the latent image carrier and adheres to the surface of the latent image carrier, and performs the refresh operation when the count value reaches a refresh request value. The image forming apparatus according to claim 1, which is executed. The functional member is a charging member that charges the latent image carrier,
The image forming apparatus according to claim 4, wherein the control unit counts the amount of the product based on a driving time of the charging member.   The image forming apparatus according to claim 4, wherein the control unit counts the amount of the product based on the number of printed sheets. Further comprising a measuring means for measuring the surrounding environment of the latent image carrier,
The image forming apparatus according to claim 1, wherein the control unit adjusts an execution timing of the refresh operation based on a measurement result by the measurement unit. An image forming station having the latent image carrier and the functional member is provided for each color along the intermediate transfer medium, and the latent image carrier of the image forming station other than the specific color is used for monochrome printing of a specific color. The image forming apparatus according to claim 1, wherein the body and the intermediate transfer medium are separated from each other.
Each of the plurality of image forming stations is provided with the refresh member and the driving unit,
The control unit is an image forming apparatus that performs a refresh operation by bringing a refresh member into contact with a latent image carrier in an image forming station other than the specific color during the monochrome printing. The image forming apparatus according to claim 1, wherein the toner image transferred to the intermediate transfer medium is transferred to a recording material.
An image forming apparatus in which a circumferential length of the latent image carrier is shorter than a length of the recording material in a rotation direction of the latent image carrier.   The image forming apparatus according to claim 1, wherein the refresh operation is performed by rotating the latent image carrier one or more times in a state where the refresh member is in contact with the surface of the latent image carrier.   The image forming apparatus according to claim 1, further comprising a cleaning member that contacts the surface of the intermediate transfer medium and cleans and removes toner remaining on the surface.   The image forming apparatus according to claim 1, wherein a toner image is formed using toner particles having a sphericity of 0.96 or more. A latent image carrier that rotates at a predetermined peripheral speed and the latent image carrier that is provided in contact with the latent image carrier in a non-contact manner or while rotating at substantially the same peripheral speed as the latent image carrier. An image forming apparatus comprising: a functional member acting on a body; and an intermediate transfer medium provided so as to come into contact with the latent image carrier while rotating at substantially the same peripheral speed as the latent image carrier. Printing is performed by charging the image carrier, forming a latent image on the latent image carrier, developing the toner on the latent image, and transferring the toner image formed by the toner development onto the intermediate transfer medium. An image forming method
Separating the refresh member from the latent image carrier during the printing process;
A step of removing the surface layer portion of the latent image carrier to refresh the latent image carrier by bringing the refreshing member into contact with the latent image carrier as necessary without performing the printing process. An image forming method comprising:

Images