JP2006154562A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus wherein a cleaning defect is not brought about by detecting environmental information of image formation and changing a timing of contact between a developer carrier and an image carrier on the basis of the detected environmental information. <P>SOLUTION: A timing at which an image carrier 1 and a developer carrier 23 are brought into contact with each other or are separated from each other is changed on the basis of information detected by an environment detection means 27. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, for example, an electrostatic latent image is formed on an image carrier by an electrophotographic method, an electrostatic recording method, etc., and the electrostatic latent image is visualized with a developer accommodated in a developing device to develop a developer image ( The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.

  Conventionally, in an electrophotographic image forming apparatus, the image carrier is generally uniformly charged by a charging device as the image carrier rotates, and then written by an exposure device such as a laser beam scanner, and an electrostatic latent image is formed on the image carrier. Form an image. The latent image is developed with a toner attached thereto by a developing device disposed opposite to the image carrier, and is visualized as a developer image, that is, a toner image.

  This toner image is directly transferred to a recording medium by a transfer device or transferred onto a recording medium via an intermediate transfer member to form an image.

  The transferred image on the recording medium after the image transfer is fixed by applying predetermined heat and pressure by, for example, a heat fixing device.

  On the other hand, untransferred developer remaining on the image carrier without being transferred after image transfer, that is, transfer residual toner, is removed by a cleaning device to prepare for the next image formation.

  Since this cleaning device has good cleaning performance, conventionally, many elastic cleaning blades made of polyurethane or the like have been employed as a cleaning member, and the tip is pressed against the image carrier.

  The physical properties of the cleaning blade and the manner of contact with the image carrier vary greatly depending on the degree of adhesion of the transfer residual toner to the image carrier, the surface property of the image carrier, etc., and also depending on the toner shape, particle size, material, etc. to differ greatly.

  Accordingly, it is necessary to select a blade suitable for each model and set it to an appropriate angle and an appropriate contact load with respect to the image carrier.

  Further, it is easily affected by changes in the operating environment, particularly temperature and humidity, and at low temperatures and low humidity, it is very difficult to follow the image carrier due to the reduced flexibility of the blade, and cleaning is difficult. In practice, the optimum cleaning blade is selected and installed by repeating trial and error.

  In recent years, an electrophotographic image forming apparatus employs a developing roller as a developer carrying member for carrying and transporting a developer in a developing device, and the photosensitive drum as an image carrying member is rotated while rotating the developing roller. A device having contact / separation means for moving to a contact and non-contact position is disclosed in Patent Document 1, for example.

In this prior art, after the photosensitive drum rotates before starting development, the developing roller is moved to a contact position with the photosensitive drum while rotating, and the developing roller is rotated while the photosensitive drum is rotated after the developing operation is completed. It is characterized by switching to a position separated from the photosensitive drum, preventing permanent deformation of the contact portion that occurs when the photosensitive drum or the developing roller contacts for a long time, and reducing wasteful consumption of developer that occurs during the separation operation. To be able to plan.
JP-A-4-43378

  However, in the case of an image forming apparatus using a one-component contact development method, if the toner on the developing roller is made thin in order to reduce the adhesion (fogging) of unnecessary toner to a white background portion and obtain a sufficient image density. At the same time, it is necessary to set the peripheral speed of the developing roller higher than the peripheral speed of the photosensitive drum. However, if the developing roller is brought into contact with the photosensitive drum at a peripheral speed faster than that of the photosensitive drum, the impact due to the speed difference or the photosensitive drum Problems such as fluctuations in rotational speed occur.

  Therefore, when such an image forming apparatus is used under low temperature and low humidity, the cleaning blade cannot follow the photosensitive drum against the impact at the time of contact and separation between the developing roller and the photosensitive drum, causing a defective cleaning, and There is a problem of vertical streaks.

  The present invention has been made in view of the above problems, and an object of the present invention is to detect environmental information in which image formation is performed, and to contact the developer carrier and the image carrier based on the detected environmental information. It is an object of the present invention to provide an image forming apparatus that does not cause a cleaning defect by changing the timing of the cleaning.

The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention relates to an image carrier on which an electrostatic latent image is formed, and a developer that contacts the image carrier and develops the electrostatic latent image on the image carrier to form a developer image. A developer carrying member that carries and transports the developer, and a cleaning unit that contacts and cleans the remaining developer obtained by transferring the developer image on the image carrier to a recording medium or an intermediate transfer member. In the image forming apparatus, comprising: a control unit that contacts and separates the image carrier and the developer carrier, and an environment detection unit.
The image forming apparatus is characterized in that the timing at which the image carrier and the developer carrier are brought into contact with or separated from each other is changed based on information detected by the environment detection unit.

  According to the present invention, it is possible to always form a high-quality image without causing defective cleaning during the contact and separation operations of the image carrier and the developer carrier.

  The image forming apparatus according to the present invention will be described below in more detail with reference to the drawings. The examples described below illustrate the present invention by way of example, and the dimensions, materials, shapes, relative arrangements, etc. of the components described below are not particularly specified unless otherwise specified. However, the scope of the present invention is not limited thereto.

Example 1
FIG. 1 shows a schematic cross section of an embodiment of an image forming apparatus according to the present invention. The image forming apparatus A according to the present embodiment is a laser beam printer that forms an image on a recording medium 6 such as a recording sheet or an OHP sheet by electrophotography in accordance with image information. In the image forming apparatus A of the present embodiment, the process cartridge B is detachable as will be described in detail later.

  The image forming apparatus A is used by being connected to a host 14 such as a personal computer. The controller unit 33 controls the scanner 3 as an exposure unit in accordance with a print request signal and an image data signal from the host 14, thereby forming an electrostatic latent image on the image carrier 1. In this embodiment, the image carrier is a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1 and is driven to rotate in the direction of arrow R1 in FIG.

  The photosensitive drum 1 is uniformly charged by a roller-shaped charging member that is in pressure contact with the photosensitive drum 1, that is, a DC contact charging roller (charging roller) 2, which is a charging unit. A DC voltage fixed to a predetermined value as a charging bias is applied to the charging roller 2 to uniformly charge the surface of the photosensitive drum 1 negatively. The charging roller 2 is driven to rotate in the direction of the arrow R2 in the figure as the photosensitive drum 1 rotates. The charging roller 2 is in contact with the entire length of the photosensitive drum 1 (the direction perpendicular to the conveyance direction of the recording medium 6).

  The uniformly charged photosensitive drum 1 is exposed by a laser beam L from a scanner 3 as an exposure unit, and an electrostatic latent image is formed on the surface thereof. The scanner 3 includes a laser light source (not shown), a polygon mirror 30a, a lens system 30b, and the like, and can scan and expose the photosensitive drum 1 under the control of the controller unit 33.

  Thereafter, the electrostatic latent image is visualized as a toner image by being supplied with a developer by the developing device 4 as a developing means.

  That is, the developing device 4 includes a developing container 21 that stores a negatively charged nonmagnetic toner 22 as a one-component developer. In this embodiment, as the toner 22, a substantially spherical toner having a weight average particle diameter of about 7 μm is used in order to achieve a small particle diameter and a low melting point, and to improve transfer efficiency.

  A part of the developing container 21 facing the photosensitive drum 1 is opened over substantially the entire longitudinal direction of the photosensitive drum 1, and a developing roller 23 that is a roller-shaped developer carrier is disposed in the opening. ing. The developing roller 23 is pressed and brought into contact with the photosensitive drum 1 located at the upper left of the developing device 4 in the figure so as to have a predetermined penetration amount, and is driven to rotate in the direction of arrow R3 in the figure. Further, the surface has moderate irregularities in order to increase the probability of rubbing with the toner 22 and to carry the toner 22 well.

  An elastic roller 24 is in contact with the developing roller 23 as a means for supplying developer to the developing roller 23 and stripping off the undeveloped toner from the developing roller 23 at the lower right in the drawing. The elastic roller 24 is rotatably supported by the developing container 21. The elastic roller 24 is a rubber sponge roller from the viewpoint of supplying toner to the developing roller 23 and stripping off undeveloped toner, and is driven to rotate in the direction of arrow R4 in the figure, which is the same direction as the developing roller 23.

  Further, the developing device 4 includes a developing blade 25 as a developer layer thickness regulating member that regulates the amount of toner carried on the developing roller 23. The developing blade 25 is made of an elastic phosphor bronze metal thin plate, and is provided so that the vicinity of the free end side is in contact with the outer peripheral surface of the developing roller 23 in surface contact. The toner carried on the developing roller 23 by rubbing against the elastic roller 24 is given a charge by frictional charging when passing through the contact portion with the developing blade 25 and is regulated to a thin layer.

  In the developing device 4 having such a configuration, a DC voltage fixed to a predetermined value as a developing bias is applied to the developing roller 23. Thus, in this embodiment, the exposed portion on the surface of the uniformly charged photosensitive drum 1 where the negative charge is attenuated is developed by reversal development.

  On the other hand, the recording medium 6 is separated and fed from the recording medium container 16 by the supply roller 12a, and is temporarily stopped by the registration roller 12b. The registration roller 12b synchronizes the recording position of the recording medium 6 with the formation timing of the toner image on the photosensitive drum 1, and moves to a facing portion (transfer portion) between the transfer roller 5 serving as transfer means and the photosensitive drum 1. The recording medium 6 is sent out.

  Thus, the visible toner image on the photosensitive drum 1 is transferred to the recording medium 6 by the action of the transfer roller 5. The recording medium 6 to which the toner image is transferred is conveyed to the fixing device 9. Here, the unfixed toner image on the recording medium 6 is permanently fixed to the recording medium 6 by heat and pressure. Thereafter, the recording medium 6 is discharged out of the apparatus by a discharge roller 12c and the like.

  Further, residual toner that remains on the photosensitive drum 1 without being transferred is cleaned by the cleaning device 10. That is, the cleaning device 10 scrapes off the transfer residual toner from the photosensitive drum 1 by the cleaning blade 8 which is a cleaning member as a cleaning unit, and stores it in the waste toner container 7. The cleaned photosensitive drum 1 is used for the next image formation.

  In this embodiment, the image forming apparatus A integrally forms an image carrier having a drum-shaped electrophotographic photosensitive member, that is, a photosensitive drum 1 and process means acting on the photosensitive drum 1 into a cartridge. It is a process cartridge system in which the cartridge is detachable from the electrophotographic image forming apparatus main body 13.

  Here, as the process means, in this embodiment, a charging means (charging roller 2) for charging the photosensitive drum 1, a developing means (developing device 4) for supplying a developer to the photosensitive drum 1, and the photosensitive drum 1 are cleaned. A cleaning means 8 (cleaning device 10) is included.

  In other words, the process cartridge means that the charging means, the developing means, the cleaning means, and the electrophotographic photosensitive member are integrally formed into a cartridge and the cartridge can be attached to and detached from the electrophotographic image forming apparatus main body 13 or the charging means. In addition, at least one of the developing unit and the cleaning unit and the electrophotographic photosensitive member are integrally formed into a cartridge so as to be detachable from the main body of the electrophotographic image forming apparatus, or at least the developing unit and the electrophotographic unit The photosensitive member is integrally formed into a cartridge, and the cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus.

  In the process cartridge B in this embodiment, the developing device 4, that is, the developing roller 23 is swingable about the support shaft 36 with respect to the photosensitive drum 1, and is pressed by a spring 37. The developing roller 23 and the photosensitive drum 1 are in contact with each other.

  In this embodiment, the photosensitive drum 1, the charging roller 2, the developing device 4, and the cleaning device 10 are integrally formed into a cartridge to form a process cartridge B that can be attached to and detached from the apparatus main body 13. The process cartridge B is detachably mounted on the apparatus main body 13 via mounting means (not shown) provided in the apparatus main body 13.

  Further, the recording medium 6 is transported to the process cartridge B by the recording medium supply roller 12a, the registration roller 12b, the discharge roller 12c, and the recording medium 6 after image formation is discharged from the apparatus main body 13. A recording medium conveying unit is configured.

  According to the present embodiment, the image forming apparatus main body 13 is provided with the environment sensor 27 as an environment detection unit so that at least temperature detection is possible.

  Further, the main body control unit 32 is arranged adjacent to the process cartridge B and in this embodiment, the contact / separation means 40 which is a cam member provided at the bottom of the developing container 21 in the direction of the arrow in FIG. Control rotation. Therefore, when the cam means 40 rotates, the developing device 4 can swing around the support shaft 36, and the contact and separation operations of the photosensitive drum 1 and the developing roller 23 are controlled. The main body control unit 32 is provided with a ROM 34 as storage means, and the process cartridge B is integrally provided with storage means 26 for storing environmental history.

  Next, the cleaning device 10 including the elastic blade 8 used in this embodiment will be described with reference to FIG.

  Referring to FIG. 2, the cleaning device 10 includes the waste toner collecting container 7, the cleaning blade 8 that is an elastic blade, and the toner collecting sheet 8B as described above.

  As described above, a small amount of toner remaining on the surface of the photosensitive drum 1 after the primary transfer is removed from the photosensitive drum 1 by the cleaning blade 8 constituting the cleaning device 10 and cleaned by the waste toner collecting sheet 8B. The toner is stored in the waste toner collecting container 7 without being scattered outside the apparatus 10.

  On the other hand, the cleaning blade 8 is made of polyurethane rubber that is integrally held at the front end of the sheet metal 8A. As shown in FIGS. 3 and 4, the cleaning blade 8 has a predetermined penetration amount δ and a set angle θ relative to the photosensitive drum 1. The contact is made under the conditions of

  The tan δ (loss factor) of the cleaning blade 8 described above has a characteristic that varies as shown in FIG. In general, when the tan δ (loss factor) of the cleaning blade 8 is high, the response to an impact from the outside of the cleaning blade 8 is low. For example, when there is a protrusion on a smooth plane, the photosensitive drum of the cleaning blade 8 with respect to the protrusion. 1 is slow in deformation, and the cleaning blade 8 is less likely to follow the surface of the photosensitive drum 1. Accordingly, when there is toner adhering to the surface of the photosensitive drum 1, a cleaning failure is likely to occur.

  On the other hand, when the tan δ (loss factor) of the cleaning blade 8 is low, when the cleaning blade 8 hits the protrusion on the surface of the photosensitive drum 1, the contact portion with the photosensitive drum 1 is quickly deformed. Follow the surface of the drum 1. Accordingly, no cleaning failure occurs with respect to the toner adhering to the surface of the photosensitive drum 1.

The tan δ (loss coefficient) is a numerical value indicating the dynamic viscoelasticity of the rubber material, and is defined by the following equation tan δ (loss coefficient) = loss elastic coefficient / storage elastic coefficient.

  The tan δ (loss factor) in FIG. 5 is measured by a Leo Vibron DDV-25FP model manufactured by Orientec Co., Ltd.

  In the present invention, based on the temperature information detected by the environment sensor 27, the main body control unit 32 operates the contact / separation cam means 40 to correct the contact and separation operations of the photosensitive drum 1 and the developing roller 23.

  The cleaning performance of the cleaning blade 8 in this embodiment is reduced in an environment of 10 ° C. or lower where tan δ (loss factor) is 0.8 or lower.

  When the tip position of the cleaning blade 8 in the present embodiment with respect to the photosensitive drum 1 is determined by the set angle θ and the penetration amount δ as shown in FIG. 3, the cleanable region at 10 ° C. or less is shown in FIG. It looks like P region.

  In this embodiment, the developing roller 23 and the photosensitive drum 1 are brought into contact with and separated from each other, and the tip position of the cleaning blade 8 is moved by each operation. During the abutting operation, the abutting pressure between the cleaning blade 8 and the photosensitive drum 1 increases, and the cleaning blade 8 comes into contact with the photosensitive drum 1, and in FIG. Move by an intrusion amount of 0.1 mm. During the separation operation, the contact pressure between the cleaning blade 8 and the photosensitive drum 1 decreases, and the cleaning blade 8 moves in a direction away from the photosensitive drum 1, and in FIG. The invasion amount moves by 0.1 mm.

  As a result, even at the tip position of the P region of FIG. 4A, it was in the Q region of FIG. 4B (corresponding to the P region of FIG. 4A) due to the impact during contact and separation. The tip position moves to the poor cleaning region in region R in FIG.

  Therefore, at 10 ° C. or lower, if the photosensitive drum 1 is driven when the developing roller 23 and the photosensitive drum 1 are in contact with or separated from each other, depending on the position of the tip of the cleaning blade 8, the toner on the photosensitive drum 1 may slip through. I will wake you up.

  In the present embodiment, the P region in FIG. 4A varies depending on the type of the cleaning blade 8 and the cartridge configuration, and is not limited to this.

  Further, in this embodiment, it is not preferable to reduce the P region of FIG. 4A so as not to cause a cleaning failure even at 10 ° C. or lower because it causes mass productivity reduction and cost increase.

  In this example, when it is not 10 ° C. or less, it can be cleaned even in the R region of FIG. 4B, which is a cleaning NG region at 10 ° C. or less, and it is understood that there is no influence at the time of contact and separation. Yes.

  Therefore, in this embodiment, when the environment sensor 27 detects an environment of 10 ° C. or lower, the contact / separation timing of the photosensitive drum 1 and the developing roller 23 is changed to prevent the cleaning failure that the toner on the photosensitive drum 1 slips through. .

  Next, a method for changing the contact / separation timing of the photosensitive drum 1 and the developing roller 23 based on the environment detection result of the present embodiment will be described using a flowchart of FIG. 6 while comparing the cleaning failure countermeasure sequence with the normal sequence. .

Sequence start.
S1: A print signal is input from the host 14.
S2: The environment sensor 27 detects the installation environment (temperature) of the image forming apparatus main body 13.
S3: It is determined whether the detected temperature is 10 ° C. or less. If it is 10 ° C. or less, the process proceeds to the cleaning failure countermeasure sequence in steps U1 to U11. Proceed to the sequence.

First, the operation of the normal sequences T1 to T9 will be described.
T1: The photosensitive drum 1 and the developing roller 23 are driven.
T2: A charging bias and a developing bias a are applied. Each is a bias at the time of image formation.
T3: The photosensitive drum 1 and the developing roller 23 are brought into contact with each other.
T4: Image formation is performed.
T5: If there is a continuous print request, the operation of step T4 is performed, and if not, the process proceeds to step T6.
T6: The photosensitive drum 1 and the developing roller 23 are separated from each other.
T7: The charging bias and development bias a are stopped.
T8: The driving of the photosensitive drum 1 and the developing roller 23 is stopped.
T9: Printing is finished.

  When the installation temperature of the image forming apparatus main body 13 is not 10 ° C. or less, by performing the operations of Steps T1 to T9, the photosensitive drum 1 and the developing roller 23 are brought into contact with and separated from each other at the time of driving, thereby forming an image.

Next, the operation of the cleaning failure countermeasure sequences U1 to U11 will be described.
U1: A development bias b is applied. The developing bias b is a bias that does not develop with respect to the surface potential of 0 V of the photosensitive drum 1 when the photosensitive drum 1 and the developing roller 23 come into contact with each other.
U2: The photosensitive drum 1 and the developing roller 23 are brought into contact with each other.
U3: The photosensitive drum 1 and the developing roller 23 are driven.
U4: A charging bias is applied. This is a bias at the time of image formation.
U5: After the operation in step U4, the developing drum a is applied after the photosensitive drum 1 makes one rotation. The development bias a is a bias at the time of image formation. The aim of the operations in steps U4 to U5 is to apply the developing bias at the time of image formation after setting the surface potential of the photosensitive drum 1 to the potential at the time of image formation.
U6: Image formation is performed.
U7: If there is a continuous print request, the operation of step U6 is performed, and if not, the process proceeds to step U8.
U8: Stop driving of the photosensitive drum 1 and the developing roller 23.
U9: The photosensitive drum 1 and the developing roller 23 are separated.
U10: The application of the charging bias and the developing bias a is stopped. By proceeding in the order of steps U8 to U10, the photosensitive drum 1 and the developing roller 23 can be separated after the driving of the photosensitive drum 1 and the developing roller 23 is stopped without causing fogging on the surface of the photosensitive drum.
U11: End printing.

  When the installation temperature of the image forming apparatus main body 13 is 10 ° C. or less, the operations of Steps U1 to U11 are performed so that the photosensitive drum 1 and the developing roller 23 come into contact with and separated from each other when the photosensitive drum 1 and the developing roller 23 are driven. An image can be formed without performing the above.

  Thereby, even when the installation temperature of the image forming apparatus main body 13 is 10 ° C. or lower, it is possible to provide an image forming apparatus that does not cause defective cleaning. Although the first print time is longer than that in the normal sequence, it does not affect continuous printing and is not a problem level.

  In this embodiment, the timing of both contact and separation between the photosensitive drum 1 and the developing roller 23 is changed in the cleaning failure countermeasure sequence. However, even when only one of the timing changes, the corresponding effect can be obtained.

  In this embodiment, the order of steps U3-U4 is used in the cleaning failure countermeasure sequence. However, even if this order is changed, the same effect is obtained.

  In this embodiment, in the operation of steps U4 to U5 in the cleaning failure countermeasure sequence, the developing bias a is applied after the photosensitive drum 1 makes one rotation. However, the surface potential of the photosensitive drum 1 becomes the potential at the time of image formation. Therefore, if the developing bias is switched to the bias at the time of image formation, the switching timing to the developing bias a is not limited to this.

Example 2
Next, another embodiment of the image forming apparatus according to the present invention will be described.

  In the present exemplary embodiment, in the image forming apparatus A described in the first exemplary embodiment, the environmental information to be detected is changed with respect to the method for changing the contact / separation operation between the photosensitive drum 1 and the developing roller 23 based on the environmental detection result. It has the same effect as.

  In this embodiment, it is assumed that the environmental information detected by the environmental sensor 27 is based on temperature and humidity, and the X environment and the Y environment shown in FIG. 7 can be detected.

  The cleaning ability of the cleaning blade 8 in this embodiment is the same as that in Embodiment 1, and the cleaning ability is reduced in an environment of 10 ° C. or less where tan δ (loss coefficient) is 0.8 or less.

  However, there is an environmental difference in the toner charge amount on the photosensitive drum in the present embodiment, and it largely depends on the absolute water content, and is −80 (μQ / g) or more in the X environment and less than that in the Y environment.

  In addition, the cleaning ability of the cleaning blade 8 is greatly related to the toner charge amount on the photosensitive drum, and is easy to clean in a Y environment where the toner charge amount is low and the image power on the drum surface is low, and the toner charge amount is high and the image force on the drum surface is high. Cleaning is difficult in high X environment.

  In the present embodiment, it was found that cleaning is possible in the Y environment even in an environment of 10 ° C. or less where tan δ (loss coefficient) is 0.8 or less.

  In view of this, the defective cleaning environment in the present embodiment is indicated by the hatched portion (Z region) in FIG. An environment that is 10 ° C. or lower and is an X environment is a Z region (cleaning poor environment).

  Therefore, in this embodiment, the environment sensor 27 detects whether the installation environment of the image forming apparatus main body 13 is in the Z region in FIG. 8. If the environment is in the Z region as in the first embodiment, cleaning is performed. Proceed to the defect countermeasure sequence. If the environment is not in the Z region, the process proceeds to the normal sequence.

  In this embodiment, even when the installation environment of the image forming apparatus main body 13 is the Z region in FIG. 8, it is possible to provide an image forming apparatus that does not cause a cleaning failure.

  In addition, since the present embodiment is a sequence in consideration of the influence of humidity, it has an effect of reducing the environment in which the cleaning failure countermeasure sequence is used as compared with the first embodiment.

Example 3
FIG. 9 shows another embodiment of the image forming apparatus of the present invention.

  The image forming apparatus of the present embodiment shown in FIG. 9 is an inline full color LBP in which the process cartridge B in the image forming apparatus A described in the first embodiment is arranged vertically.

  That is, the image forming apparatus A according to the present embodiment has four image forming stations Pa, Pb, Pc, and Pd arranged in parallel in the vertical direction, and the image forming stations Pa, Pb, Pc, and Pd are arranged in the vertical direction. The process cartridges B (Ba, Bb, Bc, Bd) are detachably mounted by mounting means (not shown).

  Each cartridge B (Ba, Bb, Bc, Bd) is the same as the process cartridge B described in the first embodiment, and members having the same configuration and function are denoted by the same reference numerals. The description in Example 1 is incorporated.

  Next, each cartridge B (Ba, Bb, Bc, Bd) and image forming operation in this embodiment will be briefly described.

  Each cartridge B (Ba, Bb, Bc, Bd) includes a drum-shaped electrophotographic photosensitive member as an image carrier, that is, a photosensitive drum 1 (1a, 1b, 1c, 1d). The photosensitive drum 1 is driven to rotate counterclockwise (R1 direction) in FIG. The photosensitive drum 1 is irradiated with a laser beam on the periphery of the photosensitive drum 1 in order according to the direction of rotation of the photosensitive drum 1 to uniformly charge the surface of the photosensitive drum 1 and a laser beam based on image information. A developing unit 4 (4a) including a scanner unit 3 (3a, 3b, 3c, 3d) for forming the upper electrostatic latent image and a developing roller 23 for developing the toner image by attaching toner to the electrostatic latent image. 4b, 4c, 4d), a cleaning belt 8 that transfers the toner image on the photosensitive drum 1 to the transfer material S, and a cleaning blade 8 that removes transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer. A device 10 (10a, 10b, 10c, 10d) or the like is disposed.

  On the other hand, the recording medium 6 is separated and fed from the recording medium container 16 by a supply roller 12a and the like, and is temporarily stopped by a registration roller 12b. Then, the timing of the image and the recording medium 6 is measured, and the recording medium 6 is conveyed from the registration roller 12b to the transfer conveyance belt 11, and the photosensitive drum 1 (1a, 1b, 1c, 1d) and the transfer roller 12 (12a, 12b). , 12c, 12d).

  Subsequently, the toner images formed on the surface of the photosensitive drum 1 are sequentially transferred onto the recording medium 6 to record a color image.

  Thereafter, when the recording medium 6 passes through the fixing unit 9, the recording medium 6 is subjected to heat treatment and pressure treatment, whereby the toner image is fixed. The recording medium 6 on which the toner image is fixed is discharged out of the apparatus by the discharge roller 12c.

  In each process cartridge B (Ba, Bb, Bc, Bd) in this embodiment, the developing roller 23 (23a, 23b, 23c, 23d) is also supported by the support shaft 36 (36a, 36b, 36c) with respect to the photosensitive drum 1. , 36d) and can be swung about the spring 37 (37a, 37b, 37c, 37d). That is, each process cartridge B is not shown in FIG. 9, but as in the first embodiment, the developing device 4, the contacting / separating means 40 (FIG. 1) provided adjacent to each process cartridge B, That is, the developing roller 23 is swung, and the developing roller 23 and the photosensitive drum 1 are in contact with and separated from each other.

  Also in this embodiment, the operations of Embodiments 1 and 2 are performed independently for the four color process cartridges B (Ba, Bb, Bc, Bd), respectively, so that the photosensitive drums 1 (1a, 1b, 1c, 1d) are obtained. ) And the developing roller 23 (23a, 23b, 23c, 23d), it is possible to eliminate the defective cleaning during the contact and separation operations.

  In this embodiment, the inline full color LBP is used, but the same effect can be obtained even in the full color LBP using the rotary method.

  In each of the above embodiments, the image forming apparatus that directly transfers the developer image (toner image) formed on the photosensitive drum 1 to the recording medium 6 has been described. However, the developer image formed on the photosensitive drum 1 has been described. In the so-called intermediate transfer type image forming apparatus in which the (toner image) is once transferred to the intermediate transfer member and then transferred from the intermediate transfer member to the recording medium 6, the above-described configuration of the present invention is applied in the same manner. The effect can be achieved.

1 is a schematic cross-sectional view of an embodiment of an image forming apparatus according to the present invention. It is a figure which shows the detail of a part of cleaning apparatus. It is a figure for demonstrating the penetration amount and setting angle of a cleaning blade. It is a figure which shows the relationship between cleaning failure, the penetration | invasion amount of a cleaning blade, and a setting angle | corner. It is a graph which shows the relationship between the temperature of a cleaning blade, and tan-delta. It is a flowchart for demonstrating one Example of the cleaning defect countermeasure sequence according to this invention. It is a figure which shows the environment which can be detected by an environment detection means. It is a figure which shows a cleaning defect environment. It is a schematic sectional drawing of the other Example of the image forming apparatus which concerns on this invention.

Explanation of symbols

1 Photosensitive drum (image carrier)
2 Charging roller (charging means)
3 Scanner (exposure means)
4 Developing device 7 Waste toner container 8 Cleaning blade (cleaning means)
DESCRIPTION OF SYMBOLS 10 Cleaning apparatus 13 Image forming apparatus main body 21 Developing container 23 Developing roller (developer carrier)
26 Non-contact memory (memory means)
27 Environmental sensor (environment detection means)
32 Main body control unit 40 Cam member (contact / separation means)
A Image forming device B Process cartridge

Claims (5)

An image carrier on which an electrostatic latent image is formed, and a developer that carries and conveys the developer, which is in contact with the image carrier and develops the electrostatic latent image on the image carrier to form a developer image A carrier, cleaning means for contacting the image carrier with the remaining developer transferred from the developer image on the image carrier to a recording medium or an intermediate transfer member, and cleaning; and the image carrier and the developer In an image forming apparatus having a control means for contacting and separating the agent carrier, and an environment detection means,
An image forming apparatus comprising: changing a timing at which the image carrier and the developer carrier are brought into contact with or separated from each other based on information detected by the environment detection unit. Based on the information detected by the environment detection means,
(1) After driving the image carrier and the developer carrier, the image carrier and the developer carrier are brought into contact with each other, and the image carrier and the developer carrier are separated from each other Stop driving the image carrier and the developer carrier, or
(2) After the image carrier and the developer carrier are brought into contact, the image carrier and the developer carrier are driven, and the drive of the image carrier and the developer carrier is stopped. Then, the image carrier and the developer carrier are separated from each other.
The image forming apparatus according to claim 1.   Based on the information detected by the environment detection means, the charging bias applied to the image carrier and / or the development bias applied to the developer carrier for forming an electrostatic latent image is determined. The image forming apparatus according to claim 1, wherein the image forming apparatus is changed.   The image forming apparatus according to claim 1, wherein the information detected by the environment detection unit includes at least temperature information.   5. The process cartridge according to claim 1, wherein the image carrier, the cleaning unit, and the developer carrier are integrally formed and are process cartridges that are detachably attached to the image forming apparatus main body. The image forming apparatus according to any one of the items.

Images