JP6171067B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that operates in an electrophotographic system.

  An electrophotographic image forming process is widely used in image forming apparatuses such as copiers, facsimile machines, and printers. An image forming apparatus operating in an electrophotographic system is equipped with one or a plurality of image forming units for forming a developer image. In general, an image forming unit includes a charging step for uniformly charging the surface of a photosensitive drum as an image carrier, an exposure step for irradiating light on the surface of the photosensitive member to form an electrostatic latent image, and a charged development. A developing step of attaching a developer to the electrostatic latent image to form a developer image on the photoreceptor, a transfer step of transferring the developer image to a medium such as paper, and the transferred developer image on the medium. A series of steps such as a fixing step for fixing is performed. When printing a single color image, one image forming unit is used, and when printing a color image, a plurality of image forming units are formed in order to form a color image by superimposing a plurality of color developer images. Unit is used.

  In such an image forming apparatus, it is required to accurately detect the life of an image forming unit whose performance deteriorates with use time. For example, it is known that a photoconductor deteriorates when its surface film wears with use time. It is important to accurately detect the life of the photoconductor because the print quality deteriorates when the photoconductor deteriorates. Japanese Patent Laid-Open No. 2001-235985 (Patent Document 1) discloses a method of counting the number of rotations of a photoconductor and detecting the lifetime of the photoconductor based on the count value and the consumption amount of developer (toner). Has been.

JP 2001-235985 A

  However, in the case of an image forming apparatus that forms a multicolor print image using a plurality of image forming units, there may be variations in the deterioration state between the image forming units.

  In view of the above, an object of the present invention is to provide an image forming apparatus capable of displaying a message prompting replacement of an image forming unit.

An image forming apparatus according to an aspect of the present invention includes a first image forming unit that forms a first developer image, and a transfer medium onto which the first developer image of the first image forming unit is transferred. A second image forming unit that is arranged alongside the first image forming unit and forms a second developer image in the transport direction of the transfer medium, and replacement of the second image forming unit. A display unit that displays a message prompting the user, and a control unit, wherein the control unit is configured so that the second image forming unit is in contact with the first image forming unit and the transfer medium. The process for forming the second developer image on the transfer medium is the first process, and the second image forming unit is in a state where the first image forming unit and the transfer medium are separated from each other. The second developer on the transfer medium The second image forming unit is replaced when the first process is executed rather than when only the second process is executed. A message prompting the user is displayed on the display unit at an early stage.
An image forming apparatus according to another aspect of the present invention includes a first image forming unit that forms a first developer image, and a transfer target onto which the first developer image of the first image forming unit is transferred. A medium, a second image forming unit that forms a second developer image, and is arranged alongside the first image forming unit in the transport direction of the transfer medium; and the second image forming unit. A display unit that displays a message for prompting replacement; and a control unit, wherein the first image forming unit forms the first developer image and the second image forming unit. The first image forming process is a process for forming the second developer image, and the second image forming unit does not form the first developer image without the first image forming unit. A process for forming the second developer image is a second process. When the image forming process is performed, the replacement of the second image forming unit is more urged when the first image forming process is executed than when only the second image forming process is executed. The message is displayed on the display unit at an early stage.

  Even when the developer used in the first image forming unit affects the life of the second image forming unit, a message prompting replacement of the second image forming unit can be displayed in view of this.

1 is a diagram schematically showing a main configuration of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a block diagram schematically showing a main configuration of a control circuit according to the first embodiment. FIG. 2 is a schematic diagram illustrating an enlarged main part of the image forming apparatus according to the first embodiment. (A), (B) is a figure which shows roughly the structural example of a photoconductor drum. 4 is a flowchart schematically illustrating a procedure of print control processing according to the first embodiment. (A), (B) is a figure which shows roughly an example of the drive mechanism which can implement | achieve arrangement | positioning change. (A) and (B) are diagrams showing a relationship between an upstream image forming unit and a downstream image forming unit. It is a graph which shows the experimental result of the film loss (unit: micrometer) of a photoconductive drum with respect to drum count. It is a block diagram which shows schematic structure of the image forming apparatus of Embodiment 2 which concerns on this invention. 10 is a flowchart schematically showing a procedure of print control processing according to the second embodiment. It is a graph which shows the experimental result of the film loss (unit: micrometer) of a photoconductive drum with respect to drum count. 2 is a diagram illustrating a main part of a direct transfer type image forming apparatus. FIG.

  Embodiments according to the present invention will be described below with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a diagram schematically showing the main configuration of an image forming apparatus 1 according to Embodiment 1 of the present invention. The image forming apparatus 1 operates by an electrophotographic method, and develops developer images of five colors of black (K), yellow (Y), magenta (M), cyan (C), and white (W) by an intermediate transfer method. It has a function of forming on a sheet-like recording medium. In the intermediate transfer method, a developer image formed on an image carrier such as a photosensitive member is transferred once to the intermediate transfer member (primary transfer), and then the developer image is transferred from the intermediate transfer member to a recording medium. (Secondary transfer). As will be described later, the present invention is not limited to the intermediate transfer method, but can also be applied to a direct transfer method in which a developer image formed on a photoreceptor is directly transferred to a recording medium.

  As shown in FIG. 1, the image forming apparatus 1 includes a cassette 11 that can store sheet-like recording media Pa in a stacked state, an intermediate transfer belt 44 that is an intermediate transfer member, and white (W) and yellow (Y ), Cyan (C), magenta (M), and black (K) developer images, respectively, and image forming units 20W, 20Y, 20C, 20M, and 20K, and a primary transfer roller 45W that forms a primary transfer portion. 45Y, 45C, 45M, 45K, a secondary transfer roller 46 that forms a secondary transfer unit, a belt cleaning unit 48 that collects the developer remaining on the intermediate transfer belt 44 after the secondary transfer, and a fixing process. A fixing unit 50 and a control circuit 60 are provided in the housing 10.

  The image forming units 20W, 20Y, 20C, 20M, and 20K are photosensitive drums 21W, 21Y, 21C, 21M, and 21K as image carriers that respectively hold W, Y, C, M, and K developer images on the surface. Built in.

  Further, the image forming apparatus 1 includes drive rollers 41 and 42 that drive the intermediate transfer belt 44 and a backup roller 43. The intermediate transfer belt 44 is an endless elastic belt made of a resin material such as polyimide resin. The intermediate transfer belt 44 is stretched (strung) around the drive rollers 41 and 42 and the backup roller 43. The driving rollers 41 and 42 and the backup roller 43 are held so as to be rotatable around a rotation axis in a direction perpendicular to the drawing. The drive rollers 41 and 42 can rotate the intermediate transfer belt 44 in the direction of the arrow by rotating clockwise in accordance with power transmitted from a drive motor (not shown).

  The image forming apparatus 1 further includes a display unit 81 and an operation input unit 82. The display unit 81 is an image display device such as a liquid crystal display panel or an organic EL display panel. The operation input unit 82 includes an input button and an input key. The control circuit 60 can display various setting screens related to the image forming apparatus 1 on the display unit 81, or can display a screen representing the operation state of the image forming apparatus 1 on the display unit 81. . The user can input information to the control circuit 60 by operating the operation input unit 82 while viewing the screen displayed on the display unit 81.

  As shown in FIG. 1, the image forming apparatus 1 includes a pickup roller 31, a feed roller 32, and a retard roller 33 in the vicinity of the cassette 11. The pickup roller 31 rotates counterclockwise and takes out the recording medium Pa from the cassette 11. The feed roller 32 and the retard roller 33 can sandwich the recording medium Pa taken out from the cassette 11 and feed it one by one to the transport path. The transport rollers 34A, 34B, 35A, 35B, 36A, and 36B transport the recording medium Pa to the secondary transfer unit.

  As the recording medium Pa, for example, plain paper, transfer paper, colored paper (plain paper with a color such as black, blue or red, not white), synthetic paper, cardboard, special paper, plastic film or cloth sheet Media. The transfer paper is a medium used for transferring a developer image to clothing such as a T-shirt. After the developer image is fixed on the transfer paper (recording medium Pa) by the image forming apparatus 1, the developer image is transferred from the transfer paper to the clothing by heat of an iron or the like.

  The image forming units 20 </ b> W, 20 </ b> Y, 20 </ b> C, 20 </ b> M, and 20 </ b> K are arranged to face the intermediate transfer belt 44 and are arranged in a line along the feeding direction of the intermediate transfer belt 44. Among these image forming units 20W, 20Y, 20C, 20M, and 20K, the image forming unit 20W that forms a white developer image is disposed on the most upstream side in the feeding direction of the intermediate transfer belt 44, and a black developer image. Is formed on the most downstream side.

  The primary transfer rollers 45W, 45Y, 45C, 45M, and 45K are disposed at positions facing the photosensitive drums 21W, 21Y, 21C, 21M, and 21K, respectively, with the intermediate transfer belt 44 interposed therebetween. These primary transfer rollers 45W, 45Y, 45C, 45M, and 45K transfer a developer image from the surface of the photosensitive drums 21W, 21Y, 21C, 21M, and 21K in contact with the intermediate transfer belt 44 to the intermediate transfer belt 44. This is a member to be transferred. The primary transfer rollers 45W, 45Y, 45C, 45M, and 45K are urged toward the image forming units 20W, 20Y, 20C, 20M, and 20K by an elastic urging member (not shown).

  The backup roller 43 and the secondary transfer roller 46 constitute a secondary transfer unit that transfers the developer image on the intermediate transfer belt 44 onto the recording medium Pa conveyed from the cassette 11. The backup roller 43 and the secondary transfer roller 46 are disposed so as to face each other and sandwich the intermediate transfer belt 44. The secondary transfer roller 46 may be composed of, for example, a metal core material and an elastic layer (for example, a foamed rubber layer) formed on the outer peripheral surface of the core material. The secondary transfer roller 46 is urged toward the backup roller 43 by an elastic urging member (not shown).

  The fixing unit 50 has a function of fixing the developer image on the recording medium Pa supplied from the secondary transfer unit to the recording medium Pa. As shown in FIG. 1, the fixing unit 50 includes a tubular heating roller 51 that rotates clockwise, and a circular pressure roller 52 that rotates counterclockwise. The pressure roller 52 is disposed to face each other. Inside the heating roller 51, a heat source (not shown) such as a halogen lamp is provided. The heating roller 51 and the pressure roller 52 melt and record the developer image by applying pressure and heat to the recording medium Pa nipped (sandwiched) between the heating roller 51 and the pressure roller 52. It can be fixed on the medium Pa.

  The recording medium Pa sent out from the fixing unit 50 is conveyed to the discharge rollers 39A and 39B by the conveying rollers 37A, 37B, 38A and 38B. The discharge rollers 39A and 39B discharge the recording medium Pa from the discharge port of the housing 10 to the discharge tray 10T. The image forming apparatus 1 includes a drive component group (not shown) such as a stepping motor that rotates the conveyance rollers 37A, 37B, 38A, and 38B and the discharge rollers 39A and 39B. The control circuit 60 can control the operation of the drive component group.

  The belt cleaning unit 48 removes the developer remaining on the intermediate transfer belt 44 after the secondary transfer. Specifically, the belt cleaning unit 48 has a built-in cleaning blade 49 that contacts the surface of the intermediate transfer belt 44 at a constant pressure, and the cleaning blade 49 is a residual developer conveyed from the secondary transfer unit. Can be scraped off from the intermediate transfer belt 44.

  Next, FIG. 2 is a block diagram schematically showing the main configuration of the control circuit 60. As shown in FIG. 2, the control circuit 60 includes a main control unit 61, a process control unit 62, a development control unit 63, a layer formation / supply voltage control unit 64, a charge control unit 65, an exposure control unit 66, and a transfer control unit. 67, a rotation drive control unit 68, an interface unit 69, a data storage unit 70, a counter unit 73, a life detection unit 74, and a position detection unit 75. A part of the function of the control circuit 60 may be realized by hardware, or may be realized by a computer program executed by a processor including one or a plurality of CPUs (Central Processing Units).

  The data storage unit 70 includes a nonvolatile memory 71 and a RAM (Random Access Memory) 72. The display unit 81 and the operation input unit 82 are connected to the main control unit 61. The non-volatile memory 71 has a storage area for storing data relating to the basic procedure of print control and information for defining a calculation formula used for correcting a count value, which will be described later, and a storage area for storing data updated as needed. . The RAM 72 is a memory used for temporarily storing data.

  The interface unit 69 has a communication interface function for receiving print job data from the host apparatus 100. The main control unit 61 generates print data based on the print job data. The process control unit 62 controls applied voltages to various rollers included in the image forming apparatus 1. The development controller 63, the layer formation / supply voltage controller 64, the charging controller 65, the exposure controller 66, the transfer controller 67, and the rotation drive controller 68 will be described later.

  The sensor group 83 includes various sensors such as a sensor for detecting the current position of the recording medium Pa on the conveyance path, a sensor for detecting the number of rotations of the photosensitive drums 21W, 21Y, 21C, 21M, and 21K, a temperature sensor, and a humidity sensor. including. The main control unit 61 can execute print control based on the detection signal supplied from the sensor group 83.

  As will be described later, the image forming apparatus 1 includes a “transfer position” between which the developer image can be transferred to the intermediate transfer belt 44 and a “non-transfer position” where the developer image cannot be transferred to the intermediate transfer belt 44. A support mechanism that movably supports each of the image forming units 20W, 20Y, 20C, 20M, and 20K is provided. When any one of the image forming units 20W, 20Y, 20C, 20M, and 20K is disposed at the transfer position, the photosensitive drum of the image forming unit is disposed at the contact position that contacts the intermediate transfer belt 44. On the other hand, when any one of the image forming units 20W, 20Y, 20C, 20M, and 20K is disposed at the non-transfer position, the photosensitive drum of the image forming unit is disposed at a separation position that is separated from the intermediate transfer belt 44. It will be. The position detector 75 detects whether each of the image forming units 20W, 20Y, 20C, 20M, and 20K is at the transfer position or the non-transfer position based on the detection signal supplied from the sensor group 83, The detection result can be output to the main control unit 61. For example, when it is not necessary to form a white developer image, the image forming unit 20 </ b> W is disposed at a non-transfer position (separated position) away from the intermediate transfer belt 44. When only the white developer image is formed, only the image forming unit 20W is disposed at the transfer position, and the other image forming units 20Y, 20C, 20M, and 20K are not transferred from the intermediate transfer belt 44. Placed in position.

  The sensor for detecting the arrangement state of the image forming units 20W, 20Y, 20C, 20M, and 20K is not particularly limited, but an optical sensor, a mechanical sensor, or a magnetic sensor can be used. For example, an IC tag such as an RFID (Radio Frequency IDentification) tag may be attached to the main body of each of the image forming units 20W, 20Y, 20C, 20M, and 20K, and a sensor that reads information on the IC tag may be provided. In this case, the position detection unit 75 can detect whether each of the image forming units 20W, 20Y, 20C, 20M, and 20K is at the transfer position based on the detection result by the sensor.

  For each print job, the counter unit 73 generates a count value Ct representing the amount of use (for example, the number of rotations) of the photosensitive drums 21W, 21Y, 21C, 21M, and 21K, and the image forming units 20W, 20Y, 20C, and 20M. , And output as 20K usage. Specifically, the count value Ct may be calculated based on the number of motor steps that is the drive output for one rotation of the photosensitive drum. For example, when each of the photosensitive drums 21W, 21Y, 21C, 21M, and 21K makes one rotation in one print job, a count value Ct of “1” can be output. The nonvolatile memory 71 includes cumulative count values AC (W), AC (Y), AC (C), AC (M), and AC (K) corresponding to the photosensitive drums 21W, 21Y, 21C, 21M, and 21K, respectively. Is stored. For each print job, the counter unit 73 adds the count value Ct or its correction value to the accumulated count values AC (W), AC (Y), AC (C), AC (M), and AC (K) and is nonvolatile. The accumulated count values AC (W), AC (Y), AC (C), AC (M), and AC (K) in the memory 71 are updated.

  The life detection unit 74 uses the accumulated count values AC (W), AC (Y), AC (C), AC (M), and AC (K) as predetermined reference values (hereinafter referred to as “lifetime count values”). In comparison, the presence / absence of the life of the photosensitive drums 21W, 21Y, 21C, 21M, and 21K, that is, the presence / absence of the life of the image forming units 20W, 20Y, 20C, 20M, and 20K is determined. The main control unit 61 can display a message on the display unit 81 according to the determination result. For example, when it is determined that the accumulated count value AC (W) has reached the life count value, the main control unit 61 displays a message indicating that the photosensitive drum 21W needs to be replaced or the image forming unit 20W needs to be replaced. 81 can be displayed. Alternatively, when it is determined that the cumulative count value AC (W) is close to the life count value, the main control unit 61 indicates that the replacement time of the photosensitive drum 21W or the replacement time of the image forming unit 20W is approaching. A message can also be displayed on the display unit 81.

  Next, the configuration and operation of the image forming units 20W, 20Y, 20C, 20M, and 20K will be described below.

  FIG. 3 is a schematic view showing an enlarged main part of the image forming apparatus 1 of FIG. As shown in FIG. 3, the image forming units 20W, 20Y, 20C, 20M, and 20K are arranged at positions facing the primary transfer rollers 45W, 45Y, 45C, 45M, and 45K, respectively, via the intermediate transfer belt 44. ing. The photosensitive drums 21W, 21Y, 21C, 21M, and 21K rotate counterclockwise under the control of the rotation drive control unit 68 in FIG.

  The image forming unit 20W that forms a white developer image includes a developer accommodating portion 22W that accommodates the white developer, and a charging roller 23W that contacts the surface of the photosensitive drum 21W and uniformly charges the surface thereof. An LED head (exposure unit) 24W that performs exposure for forming an electrostatic latent image corresponding to an image to be printed on the surface of the rotating photosensitive drum 21W, a developing roller 26W that is a developer carrier, and white A supply roller 25W for supplying the developer to the developing roller 26W, a layer forming blade 27W for thinning the developer image, and a cleaning blade 28W for scraping off the developer remaining on the photosensitive drum 21W after the primary transfer. Have

  The developing roller 26W and the supply roller 25W can rotate at a speed synchronized with the rotational speed of the photosensitive drum 21W by meshing with a gear (not shown) provided at one end in the longitudinal direction of the photosensitive drum 21W. .

  The developing roller 26W is configured, for example, by covering an outer periphery of a metal shaft with an elastic body. As the elastic body on the metal shaft, for example, semiconductive urethane rubber having a rubber hardness of 70 ° (Asker C) may be used. Moreover, the supply roller 25W is comprised by coat | covering a foam on the outer periphery of a metal shaft, for example. For example, a silicon foam having a hardness of 50 ° (Asker F) may be formed as the foam.

  In accordance with the rotation of the photosensitive drum 21W, the charging roller 23W also rotates with the photosensitive drum 21W to uniformly charge the surface of the photosensitive drum 21W. At this time, a predetermined voltage is applied to the charging roller 23W under the control of the charging control unit 65 in FIG. The LED head 24W operates under the control of the exposure control unit 66 in FIG. 2, and irradiates the photosensitive drum 21W with a pattern of light corresponding to the print data to form an electrostatic latent image on the photosensitive drum 21W. .

  On the other hand, the developer held on the supply roller 25W is supplied to the surface of the development roller 26W. When the developer on the surface of the developing roller 26 </ b> W passes through the layer forming blade 27 </ b> W, the developer is subjected to a shearing force by the layer forming blade 27 </ b> W and its layer thickness is regulated and becomes uniform. At this time, predetermined voltages are respectively applied to the supply roller 25W and the layer formation blade 27W under the control of the layer formation / supply voltage control unit 64.

  When the portion of the surface of the photosensitive drum 21W where the electrostatic latent image is formed reaches the developing roller 26W, the white developer is exposed to light by the potential difference between the electrostatic latent image on the photosensitive drum 21W and the developing roller 26W. It moves onto the body drum 21WY to form a white developer image (toner image). At this time, a predetermined voltage is applied to the developing roller 26W under the control of the developing control unit 63 in FIG. Thereafter, the developer image on the photosensitive drum 21W is conveyed to the primary transfer position and transferred onto the intermediate transfer belt 44 by the primary transfer roller 45W. At this time, a predetermined voltage is applied to the primary transfer roller 45W under the control of the transfer control unit 67 in FIG.

  The other image forming units 20Y, 20C, 20M, and 20K have the same configuration as the image forming unit 20W except for the developer to be stored. That is, the image forming unit 20Y for forming a yellow developer image includes a developer accommodating portion 22Y that accommodates a yellow developer, and a charging roller that contacts the surface of the photosensitive drum 21Y and uniformly charges the surface. 23Y, an LED head (exposure unit) 24Y that performs exposure for forming an electrostatic latent image corresponding to an image to be printed on the surface of the rotating photosensitive drum 21Y, and a developing roller 26Y that is a developer carrier. A supply roller 25Y for supplying the yellow developer to the developing roller 26Y, a layer forming blade 27Y for thinning the developer image, and a cleaning blade for scraping off the developer remaining on the photosensitive drum 21Y after the primary transfer. 28Y.

  The image forming unit 20C that forms a cyan developer image includes a developer accommodating portion 22C that accommodates the cyan developer, and a charging roller that contacts the surface of the photosensitive drum 21C and uniformly charges the surface thereof. 23C, an LED head (exposure unit) 24C that performs exposure for forming an electrostatic latent image corresponding to an image to be printed on the surface of the rotating photosensitive drum 21C, and a developing roller 26C that is a developer carrier. A supply roller 25C for supplying cyan developer to the developing roller 26C, a layer forming blade 27C for thinning the developer image, and a cleaning blade for scraping off the developer remaining on the photosensitive drum 21C after the primary transfer. 28C.

  The image forming unit 20M that forms a magenta developer image includes a developer accommodating portion 22M that accommodates the magenta developer, and a charging roller that contacts the surface of the photosensitive drum 21M and uniformly charges the surface. 23M, an LED head (exposure unit) 24M that performs exposure for forming an electrostatic latent image corresponding to an image to be printed on the surface of the rotating photosensitive drum 21M, and a developing roller 26M that is a developer carrier. A supply roller 25M for supplying a magenta developer to the developing roller 26M, a layer forming blade 27M for thinning the developer image, and a cleaning blade for scraping off the developer remaining on the photosensitive drum 21M after the primary transfer. 28M.

  The image forming unit 20K that forms a black developer image includes a developer accommodating portion 22K that accommodates the black developer, and a charging roller that contacts the surface of the photosensitive drum 21K and uniformly charges the surface. 23K, an LED head (exposure unit) 24K that performs exposure for forming an electrostatic latent image corresponding to an image to be printed on the surface of the rotating photosensitive drum 21K, and a developing roller 26K that is a developer carrier. A supply roller 25K for supplying black developer to the developing roller 26K, a layer forming blade 27K for thinning the developer image, and a cleaning blade for scraping off the developer remaining on the photosensitive drum 21K after the primary transfer. 28K.

  Each of the photosensitive drums 21W, 21Y, 21C, 21M, and 21K includes, for example, a conductive support such as aluminum, and an organic photoconductor (OPC) formed around the conductive support. And a photosensitive layer. 4A and 4B are diagrams schematically showing a configuration example of the photosensitive drum 21W. As shown in FIG. 4A, the photosensitive drum 21 </ b> W includes a drum gear 211 formed around one end portion of the shaft-like conductive support 210, and around the other end portion of the conductive support 210. The drum flange 212 is formed, and a photosensitive layer 213 coated around the conductive support 210.

  FIG. 4B is a diagram schematically illustrating an example of a cross-sectional structure of the photosensitive layer 213. As shown in FIG. 4B, the photosensitive layer 213 has a structure in which a blocking layer 213b, a charge generation layer 213c, and a charge transport layer 213d are stacked on a conductive support 210. The charge transport layer 213d may be formed by coating so as to have a thickness of about 18 μm, for example. For measurement of the film thickness of the charge transport layer 213d, an eddy current film thickness meter “LH-200J” manufactured by Kett Science Laboratory Co., Ltd. can be used. The other photoconductive drums 21Y, 21C, 21M, and 21K have the same structure as the photoconductive drum 21W.

  The LED head 24W in FIG. 2 includes a plurality of LED elements (light emitting diode elements) arranged along the longitudinal direction (axial direction) of the photosensitive drum 21W, an LED driving unit that drives these LED elements, and the LED elements. Lens array for guiding the emitted light to the surface of the photosensitive drum 21W. The other LED heads 24Y, 24C, 24M, and 24K have the same configuration as the LED head 24W.

  As the developer of white (W), yellow (Y), cyan (C), magenta (M) and black (K), for example, pulverized toner manufactured by a pulverization method can be used. Without being limited, it is possible to use a toner produced by a known production method such as a polymerization method. The pulverized toner manufacturing process includes, for example, a step of melt kneading and cooling a toner raw material composed of a binder resin, a colorant, a release agent, a charge control agent, and the like to form a melt kneaded product, A step of generating toner base particles having an average particle diameter of about 8 μm by pulverization and classification, and a step of adding a non-magnetic one-component developer by adding an external additive such as hydrophobic silica to the toner base particles. It consists of. As the binder resin, for example, a polyester resin can be used.

  For black, yellow, magenta and cyan colorants, organic pigments such as carbon black, pigment yellow, pigment magenta, and pigment cyan may be used, respectively. It is desirable to use White colorants are opaque colorants that use metallic pigments, such as titanium dioxide.

  Next, the operation of the image forming apparatus 1 having the above configuration will be described below.

  FIG. 5 is a flowchart schematically showing the procedure of the print control process by the image forming apparatus 1. Referring to FIG. 5, the main control unit 61 in FIG. 2 stands by until print job data including image data is received (NO in step S10). When the main control unit 61 receives print job data including image data via the interface unit 69 (YES in step S10), the position detection unit 75 based on the detection signal from the sensor group 83, the image forming unit 20W. , 20Y, 20C, 20M, and 20K are detected (step S11). Specifically, the position detection unit 75 detects whether each of the image forming units 20W, 20Y, 20C, 20M, and 20K is disposed at the transfer position.

  Then, the main control unit 61 determines whether or not it is necessary to change the arrangement of any of the image forming units 20W, 20Y, 20C, 20M, and 20K according to the print data (step S12). When it is determined that the layout change is unnecessary (NO in step S12), the main control unit 61 shifts the procedure to the printing process in step S14.

  On the other hand, when it is determined that the arrangement change is necessary (YES in step S12), the main control unit 61 transfers the arrangement of the image forming units that need to be changed among the image forming units 20W, 20Y, 20C, 20M, and 20K. The position is changed from one of the position and the non-transfer position to the other (step S13). Specifically, the main control unit 61 may cause the display unit 81 to display a message for prompting a layout change by manual operation (manual operation), or may automatically change the layout.

  6A and 6B are diagrams schematically showing an example of a drive mechanism that can realize automatic arrangement change. FIG. 6A is a diagram showing a state in which the image forming unit 20W is disposed at the transfer position (that is, a state in which the photosensitive drum 21W of the image forming unit 20W is in the contact position), and FIG. These are diagrams showing a state in which the image forming unit 20W is disposed at the non-transfer position (a state where the photosensitive drum 21W is at the separation position). As shown in FIGS. 6A and 6B, projections 29a and 29b that engage with the guide grooves 90g of the frame 90 are provided at the longitudinal ends of the image forming unit 20W. The drive mechanism includes a cam member 91 disposed below the end and a drive motor 92 that drives the cam member 91. When the drive motor 92 rotates the cam member 91 counterclockwise around the rotation shaft 91a, as shown in FIG. 6B, the cam member 91 moves the end of the image forming unit 20W to the non-transfer position. It will be lifted upward. When the drive motor 92 rotates the cam member 91 clockwise around the rotation shaft 91a, the end of the image forming unit 20W returns to the transfer position.

  After the arrangement change (step S13) is completed, the control circuit 60 executes a printing process (step S14). Specifically, as described above, of the image forming units 20W, 20Y, 20C, 20M, and 20K, the image forming unit disposed at the transfer position transfers the developer image corresponding to the print data to the intermediate transfer belt 44. Let Next, the secondary transfer roller 46 transfers the developer image onto the recording medium Pa conveyed from the cassette 11. Next, the fixing unit 50 fixes the developer image on the recording medium Pa. Thereafter, the recording medium Pa is discharged to the discharge tray 10T. Such a printing process may be performed on one recording medium Pa, or may be continuously performed on a plurality of recording media Pa designated by print job data. Of the image forming units 20W, 20Y, 20C, 20M, and 20K, the image forming unit disposed at the non-transfer position is not driven and is not driven.

  After completion of the printing process (step S14), the main control unit 61 acquires the count value Ct from the counter unit 73 (step S15). Next, when the white image forming unit 20W is not at the transfer position (NO in step S16), the main control unit 61 shifts the process to step S19.

  On the other hand, when the image forming unit 20W is at the transfer position (YES in step S16), the counter unit 73 adds the count value Ct to the accumulated count value AC (W) stored in the nonvolatile memory 71 for the photosensitive drum 21W. Is added to update the accumulated count value AC (W) (step S17). Next, the counter unit 73 corrects the count value Ct for each color and calculates corrected count values CT (K), CT (M), CT (C), and CT (Y) (step S18). Here, the correction count values CT (K), CT (M), CT (C), and CT (Y) are correction values corresponding to the photosensitive drums 21K, 21M, 21C, and 21Y, respectively.

The counter unit 73 can calculate the correction count values CT (K), CT (M), CT (C), and CT (Y) according to the following formulas (1) to (4), for example.
CT (K) = α ₁ × Ct (1)
CT (M) = β ₁ × Ct (2)
CT (C) = γ ₁ × Ct (3)
CT (Y) = δ ₁ × Ct (4)

Here, α ₁ , β ₁ , γ ₁ and δ ₁ are correction coefficients exceeding 1, and are values that can be individually set in advance.

  Next, the main control unit 61 determines whether or not the image forming unit 20K is in the transfer position (step S19). If the image forming unit 20K is not in the transfer position (NO in step S19), step S21 is performed. Shift processing to.

  On the other hand, when the image forming unit 20K is at the transfer position (YES in step S19), the counter unit 73 adds the count value Ct to the accumulated count value AC (K) stored in the nonvolatile memory 71 for the photosensitive drum 21K. Alternatively, the cumulative count value AC (K) is updated by adding the correction count value CT (K) (step S20). That is, when the image forming unit 20W is at the transfer position (YES in step S16), the counter unit 73 adds the correction count value CT (K) to the cumulative count value AC (K), and the image forming unit 20W transfers the image. If not (NO at step S16), the count value Ct is added to the accumulated count value AC (K).

  Next, the main control unit 61 determines whether or not the image forming unit 20M is at the transfer position (step S21). If the image forming unit 20M is not at the transfer position (NO in step S21), step S23 is performed. Shift processing to.

  On the other hand, when the image forming unit 20M is at the transfer position (YES in step S21), the counter unit 73 adds the count value Ct to the accumulated count value AC (M) stored in the nonvolatile memory 71 for the photosensitive drum 21M. Alternatively, the cumulative count value AC (M) is updated by adding the correction count value CT (M) (step S22). That is, when the image forming unit 20W is at the transfer position (YES in Step S16), the counter unit 73 adds the correction count value CT (M) to the cumulative count value AC (M), and the image forming unit 20W If it is not in the contact position (NO in step S16), the count value Ct is added to the cumulative count value AC (M).

  Next, the main controller 61 determines whether or not the image forming unit 20C is at the transfer position (step S23). If the image forming unit 20C is not at the transfer position (NO in step S23), step S25 is performed. Shift processing to.

  On the other hand, when the image forming unit 20C is at the transfer position (YES in step S23), the counter unit 73 adds the count value Ct to the accumulated count value AC (C) stored in the nonvolatile memory 71 for the photosensitive drum 21C. Alternatively, the cumulative count value AC (C) is updated by adding the correction count value CT (C) (step S24). That is, when the image forming unit 20W is at the transfer position (YES in step S16), the counter unit 73 adds the correction count value CT (C) to the accumulated count value AC (C), and the image forming unit 20W transfers the image. If it is not at the position (NO in step S16), the count value Ct is added to the accumulated count value AC (C).

  Next, the main control unit 61 determines whether or not the image forming unit 20Y is in the transfer position (step S25). If the image forming unit 20Y is not in the transfer position (NO in step S25), step S27 is performed. Shift processing to.

  On the other hand, when the image forming unit 20Y is at the transfer position (YES in step S25), the counter unit 73 adds the count value Ct to the accumulated count value AC (Y) stored in the nonvolatile memory 71 for the photosensitive drum 21Y. Alternatively, the cumulative count value AC (Y) is updated by adding the correction count value CT (Y) (step S26). That is, when the image forming unit 20W is at the transfer position (YES in step S16), the counter unit 73 adds the correction count value CT (Y) to the cumulative count value AC (Y), and the image forming unit 20W transfers the image. If not (NO at step S16), the count value Ct is added to the accumulated count value AC (Y).

  Thereafter, the life detection unit 74 uses the accumulated count values AC (W), AC (K), AC (Y), AC (C), and AC (M) as the life count values TH (W), TH (K), TH. Comparison is made with (Y), TH (C), and TH (M), respectively (step S27). If it is determined that one of the photosensitive drums 21W, 21Y, 21C, 21M, and 21K has a lifetime based on the comparison result (YES in step S28), the main control unit 61 displays a drum replacement message on the display unit 81. (Step S29). On the other hand, when it is determined that there is no life (NO in step S28), the main control unit 61 ends the above print control processing.

  As described above, in the present embodiment, when the white image forming unit 20W is at the transfer position, the count value Ct is increased by correction for the photosensitive drums 21Y, 21C, 21M, and 21K for other colors. (Step S18 in FIG. 5) When the white image forming unit 20W is in the non-transfer position (separated position), the count value Ct is not corrected for the photosensitive drums 21Y, 21C, 21M, and 21K for other colors. Therefore, it is possible to accurately detect the lifetime of the photoconductive drums 21Y, 21C, 21M, and 21K.

  7A and 7B are views showing the relationship between the upstream image forming unit 20W and the downstream image forming unit 20K. FIG. 7A shows the relationship when the upstream image forming unit 20W is at the transfer position, and FIG. 7B shows the case when the upstream image forming unit 20W is at the non-transfer position (separated position). Shows the relationship. When the white developer Tw is conveyed from the upstream side to the downstream image forming unit 20K, first, it is rubbed between the photosensitive drum 21K and the intermediate transfer belt 44. Next, reverse transfer of the developer Tw from the intermediate transfer belt 44 to the photosensitive drum 21K occurs, and the developer Tw is conveyed to the cleaning blade 28K. At this time, the surface film of the photosensitive drum 21K is scraped by the pressure between the photosensitive drum 21K and the primary transfer roller 45K and the pressure between the photosensitive drum 21K and the cleaning blade 28K, and the photosensitive drum. 21K deteriorates. Further, if the surface film of the photoconductive drum 21K is worn, the charging process is not normally performed, and for example, development may occur in a blank area, and background staining may occur. Such deterioration of the photosensitive drum 21K is likely to occur due to the fact that the colorant constituting the white developer is mainly composed of a relatively hard metal pigment as described above.

FIG. 8 is a graph showing experimental results of film loss (unit: μm) of the surface film of the photosensitive drum 21K with respect to the drum count (count value Ct). The graph of FIG. 8 shows the case where the upstream image forming unit 20W is at the transfer position (white is upstream) and the case where the upstream image forming unit 20W is at the non-transfer position (separated position) (no white is upstream). ), There is a difference in the amount of abrasion of the surface film of the photosensitive drum 21K, and the film loss is different. From the results of this graph, it is understood that it is sufficient to set the correction coefficient alpha ₁ about 1.8 times. For example, the life count values TH (W), TH (K), TH (Y), TH (C), and TH (M) can be set to values around 40000 times.

Embodiment 2. FIG.
Next, a second embodiment according to the present invention will be described. FIG. 9 is a block diagram illustrating a schematic configuration of the image forming apparatus 2 according to the second embodiment. The configuration of the image forming apparatus 2 according to the present embodiment is different from the configuration of the image forming unit 20G in place of the image forming unit 20W in FIG. The configuration is the same as that of the image forming apparatus 1 of the first embodiment.

  The image forming unit 20G of the present embodiment has the same configuration as the image forming unit 20W except that it includes a photosensitive drum 21G and uses gloss toner. Gross toner is a developer used when it is desired to give gloss or gloss to the surface of a printed image. The gloss toner can be produced according to the above-described pulverization method or polymerization method, but is a colorless and transparent developer because it does not contain a pigment. The average particle size of the gloss toner produced by the pulverization method can be about 8 μm.

  Hereinafter, the operation of the image forming apparatus 2 of the present embodiment will be described.

  FIG. 10 is a flowchart schematically showing a procedure of print control processing by the image forming apparatus 2. Referring to FIG. 10, the main control unit 61 in FIG. 2 stands by until print job data including image data is received (NO in step S30). When the main control unit 61 receives print job data including image data via the interface unit 69 (YES in step S30), the position detection unit 75 based on the detection signal from the sensor group 83, the image forming unit 20G. , 20Y, 20C, 20M, and 20K are detected (step S31). Specifically, the position detection unit 75 detects whether each of the image forming units 20G, 20Y, 20C, 20M, and 20K is arranged at the transfer position, as in the case of the first embodiment.

  Then, the main control unit 61 determines whether or not it is necessary to change the arrangement of any of the image forming units 20G, 20Y, 20C, 20M, and 20K according to the print data (step S32). When it is determined that the layout change is unnecessary (NO in step S32), the main control unit 61 shifts the procedure to the printing process in step S34.

  On the other hand, when it is determined that the arrangement change is necessary (YES in step S32), the main control unit 61 transfers the arrangement of the image forming units that need to be changed among the image forming units 20G, 20Y, 20C, 20M, and 20K. The position is changed from one of the position and the non-transfer position to the other (step S33). Specifically, the main control unit 61 may cause the display unit 81 to display a message for prompting a layout change by manual operation (manual operation), or may automatically change the layout.

  After the arrangement change (step S33) is completed, the control circuit 60 executes a printing process (step S34). Specifically, as described above, the image forming unit at the transfer position among the image forming units 20G, 20Y, 20C, 20M, and 20K transfers the developer image corresponding to the print data to the intermediate transfer belt 44. Next, the secondary transfer roller 46 transfers the developer image onto the recording medium Pa conveyed from the cassette 11. Next, the fixing unit 50 fixes the developer image on the recording medium Pa. Thereafter, the recording medium Pa is discharged to the discharge tray 10T. Such a printing process may be performed on one recording medium Pa, or may be continuously performed on a plurality of recording media Pa designated by print job data. When the image forming unit 20G is in the non-transfer position (separated position), the image forming unit 20G is not driven because it is not applied with a voltage.

  After the completion of the printing process (step S34), the main control unit 61 acquires the count value Ct from the counter unit 73 (step S35). Next, when the image forming unit 20G is not in the contact position (NO in step S36), the main control unit 61 shifts the process to step S19.

  On the other hand, when the image forming unit 20G is at the transfer position (YES in step S36), the counter unit 73 adds the count value Ct to the accumulated count value AC (G) stored in the nonvolatile memory 71 for the photosensitive drum 21G. Is added to update the accumulated count value AC (G) (step S37). Next, the counter unit 73 corrects the count value Ct for each color and calculates corrected count values CT (K), CT (M), CT (C), and CT (Y) (step S38). Here, the correction count values CT (K), CT (M), CT (C), and CT (Y) are correction values corresponding to the photosensitive drums 21K, 21M, 21C, and 21Y, respectively.

The counter unit 73 can calculate the correction count values CT (K), CT (M), CT (C), and CT (Y) according to the following formulas (5) to (8), for example.
CT (K) = α ₂ × Ct (5)
CT (M) = β ₂ × Ct (6)
CT (C) = γ ₂ × Ct (7)
CT (Y) = δ ₂ × Ct (8)

Here, α ₂ , β ₂ , γ ₂ , and δ ₂ are correction coefficients in the range of 0 or more and less than 1, and are values that can be individually set in advance.

  Next, the main control unit 61 determines whether or not the image forming unit 20K is in the transfer position (step S39). If the image forming unit 20K is not in the transfer position (NO in step S39), step S41 is performed. Shift processing to.

  On the other hand, when the image forming unit 20K is at the transfer position (YES in step S39), the counter unit 73 adds the count value Ct to the cumulative count value AC (K) stored in the nonvolatile memory 71 for the photosensitive drum 21K. Alternatively, the cumulative count value AC (K) is updated by adding the correction count value CT (K) (step S40). That is, when the image forming unit 20G is at the transfer position (YES in Step S36), the counter unit 73 adds the correction count value CT (K) to the accumulated count value AC (K), and the image forming unit 20G transfers the image. If not (NO at step S36), the count value Ct is added to the accumulated count value AC (K).

  Next, the main controller 61 determines whether or not the image forming unit 20M is at the transfer position (step S41). If the image forming unit 20M is not at the transfer position (NO in step S41), step S43 is performed. Shift processing to.

  On the other hand, when the image forming unit 20M is at the transfer position (YES in step S41), the counter unit 73 adds the count value Ct to the accumulated count value AC (M) stored in the nonvolatile memory 71 for the photosensitive drum 21M. Alternatively, the cumulative count value AC (M) is updated by adding the correction count value CT (M) (step S42). That is, when the image forming unit 20G is at the transfer position (YES in step S36), the counter unit 73 adds the correction count value CT (M) to the accumulated count value AC (M), and the image forming unit 20G transfers the image. If it is not at the position (NO in step S36), the count value Ct is added to the accumulated count value AC (M).

  Next, the main controller 61 determines whether or not the image forming unit 20C is at the transfer position (step S43). If the image forming unit 20C is not at the transfer position (NO in step S43), step S25 is performed. Shift processing to.

  On the other hand, when the image forming unit 20C is at the transfer position (YES in step S43), the counter unit 73 adds the count value Ct to the accumulated count value AC (C) stored in the nonvolatile memory 71 for the photosensitive drum 21C. Alternatively, the cumulative count value AC (C) is updated by adding the correction count value CT (C) (step S44). That is, when the image forming unit 20G is at the transfer position (YES in Step S36), the counter unit 73 adds the correction count value CT (C) to the cumulative count value AC (C), and the image forming unit 20G transfers the image. If it is not at the position (NO in step S36), the count value Ct is added to the accumulated count value AC (C).

  Next, the main controller 61 determines whether or not the image forming unit 20Y is at the transfer position (step S45). If the image forming unit 20Y is not at the transfer position (NO in step S25), step S47 is performed. Shift processing to.

  On the other hand, when the image forming unit 20Y is at the transfer position (YES in step S45), the counter unit 73 adds the count value Ct to the accumulated count value AC (Y) stored in the nonvolatile memory 71 for the photosensitive drum 21Y. Alternatively, the cumulative count value AC (Y) is updated by adding the correction count value CT (Y) (step S46). That is, when the image forming unit 20G is at the transfer position (YES in step S36), the counter unit 73 adds the correction count value CT (Y) to the cumulative count value AC (Y), and the image forming unit 20G transfers the image. If not (NO at step S36), the count value Ct is added to the accumulated count value AC (Y).

  Thereafter, the life detection unit 74 uses the accumulated count values AC (G), AC (K), AC (Y), AC (C), and AC (M) as the life count values TH (G), TH (K), TH. Comparison is made with (Y), TH (C), and TH (M), respectively (step S47). If it is determined that one of the photosensitive drums 21G, 21Y, 21C, 21M, and 21K has a lifetime based on the comparison result (YES in step S48), the main control unit 61 displays a drum replacement message on the display unit 81. (Step S49). On the other hand, when it is determined that there is no life (NO in step S48), the main control unit 61 ends the above print control processing.

  As described above, in the present embodiment, when the image forming unit 20G is at the transfer position, the count value Ct is reduced by correction for the photosensitive drums 21Y, 21C, 21M, and 21K for other colors (FIG. When the image forming unit 20G is in the non-transfer position (separated position), the count value Ct is not corrected for the photosensitive drums 21Y, 21C, 21M, and 21K for other colors. Therefore, it is possible to accurately detect the lifetime of the photoconductive drums 21Y, 21C, 21M, and 21K.

FIG. 11 is a graph showing experimental results of film loss (unit: μm) of the surface film of the photosensitive drum 21K with respect to the drum count (count value Ct). The graph of FIG. 11 shows the case where the upstream image forming unit 20G is at the transfer position (there is gloss toner on the upstream side), and the case where the upstream image forming unit 20W is at the non-transfer position (separated position) (the gloss is upstream). This indicates that there is a difference in the amount of abrasion of the surface film of the photosensitive drum 21K, and the amount of film loss is different. This is because the gloss toner does not contain a pigment harder than the resin, so that the number of times the black pigment rubs against the surface of the photosensitive drum 21K is reduced. From the results of this graph, it is understood that it is sufficient to set the correction coefficient alpha ₂ of about 0.2 times.

Modifications of the first and second embodiments.
As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable. For example, the first and second embodiments are the tandem image forming apparatuses 1 and 2, but are not limited thereto. The present invention can also be applied to a four-cycle image forming apparatus.

  In the first and second embodiments, as a preferred example, the image forming unit 20W or the image forming unit 20G is arranged at the most upstream position, but the image forming unit 20W or the image forming unit 20G is disposed at the most downstream position. You may arrange in. In this case, even when the developer that could not be removed by the belt cleaning unit is conveyed to the image forming unit for other colors and affects the life of the photosensitive drum, the life of the photosensitive drum can be accurately detected. Can do.

  Further, the first and second embodiments have five image forming units for forming developer images of five colors, but two to four images for forming developer images of two to four colors. The configuration can be changed to have a forming unit.

  The image forming apparatuses 1 and 2 according to the first and second embodiments operate in the intermediate transfer method, but the present invention is not limited to this. The present invention can also be applied to a direct transfer type image forming apparatus. FIG. 12 is a diagram illustrating a main part of a direct transfer type image forming apparatus.

  As shown in FIG. 12, the image forming apparatus includes a transfer belt 144 that conveys a recording medium Pa on the surface, and image forming units 120K, 120Y, 120M, 120C, and 120W arranged on the transfer belt 144. And a belt cleaning unit 148 that scrapes off the residual developer from the transfer belt 144. The transfer belt 144 is stretched (strung) between the pair of drive rollers 101 and 102.

  The image forming units 120K, 120Y, 120M, 120C, and 120W have a function of forming developer images of black (K), yellow (Y), magenta (M), cyan (C), and white (W), respectively. As shown in FIG. 13, the image forming unit 120K includes a developer accommodating portion 122K that accommodates a black developer, and a charging roller 123K that contacts the surface of the photosensitive drum 121K and uniformly charges the surface thereof. An LED head (exposure unit) 124K that performs exposure for forming an electrostatic latent image on the surface of the photosensitive drum 121K, a developing roller 126K, a supply roller 125K that supplies black developer to the developing roller 126K, A layer forming blade 127K for thinning the developer image and a cleaning blade 128K for scraping off the developer remaining on the photosensitive drum 121K after the transfer are provided.

  Similarly, the image forming unit 120Y includes a developer accommodating portion 122Y that accommodates a yellow developer, a charging roller 123Y, an LED head (exposure portion) 124Y, a developing roller 126Y, a supply roller 125Y, a layer forming blade 127Y, and a cleaning blade 128K. Have The image forming unit 120M includes a developer container 122M that stores a magenta developer, a charging roller 123M, an LED head (exposure unit) 124M, a developing roller 126M, a supply roller 125M, a layer forming blade 127M, and a cleaning blade 128M. The image forming unit 120C includes a developer accommodating portion 122C that accommodates a cyan developer, a charging roller 123C, an LED head (exposure portion) 124C, a developing roller 126C, a supply roller 125C, a layer forming blade 127C, and a cleaning blade 128C. The image forming unit 120W includes a developer accommodating portion 122W that accommodates a white developer, a charging roller 123W, an LED head (exposure portion) 124W, a developing roller 126W, a supply roller 125W, a layer forming blade 127W, and a cleaning blade 128W. Have.

  If the present invention is applied to the direct transfer type image forming apparatus shown in FIG. 13, the white developer that could not be completely removed by the cleaning blade 149 of the belt cleaning unit 148 is transferred to the image forming units 120K, 120Y, and Even when the photoconductor drums 121K, 121Y, 121M, and 121C are affected by being transported to 120M and 120C, the life of the photoconductor drums 121K, 121Y, 121M, and 121C can be accurately detected.

  The present invention can be applied to a printer, but is not limited to a printer, and can also be applied to a copying machine, a facsimile machine, or an MFP (Multi Function Peripheral). Note that the MFP is an image forming apparatus having the functions of a plurality of devices such as a copying machine, a printer, an image scanner, and a facsimile device.

  1, 2, 3 Image forming apparatus, 10 housing, 10T discharge tray, 11 cassette, 20W, 20Y, 20C, 20M, 20K, 20G Image forming unit, 22W, 22Y, 22C, 22M, 22K, 22G Developer container 23W, 23Y, 23C, 23M, 23K, 23G Charging roller, 24W, 24Y, 24C, 24M, 24K, 24G LED head, 25W, 25Y, 25C, 25M, 25K, 25G Supply roller, 26W, 26Y, 26C, 26M , 26K, 26G Developing roller, 27W, 27Y, 27C, 27M, 27K, 27 layer forming blade, 28W, 28Y, 28C, 28M, 28K, 28G Cleaning blade, 31 pickup roller, 32 feed roller, 33 retard roller, 43 back roller Up roller, 44 Intermediate transfer belt, 45W, 45Y, 45C, 45M, 45K, 45G Primary transfer roller, 46 Secondary transfer roller, 48 Belt cleaning unit, 49 Cleaning blade, 50 Fixing unit, 51 Heating roller, 52 Pressure Roller, 60 control circuit, 61 main control unit, 62 process control unit, 63 development control unit, 64 layer formation / supply voltage control unit, 65 charge control unit, 66 exposure control unit, 67 transfer control unit, 68 rotation drive control unit 69 interface unit, 70 data storage unit, 71 non-volatile memory, 72 RAM (Random Access Memory), 73 counter unit, 74 life detection unit, 75 position detection unit, 81 display unit, 82 operation input unit, 83 sensor group 84 Uni Gate drive unit, 100 higher-level device.

Claims (22)

A first image forming unit for forming a first developer image;
A transfer medium onto which the first developer image of the first image forming unit is transferred;
A second image forming unit that is arranged side by side with the first image forming unit in the transport direction of the transfer medium and forms a second developer image;
A display for displaying a message prompting replacement of the second image forming unit;
A control unit,
The controller is
A process in which the second image forming unit forms the second developer image on the transfer medium while the first image forming unit is in contact with the transfer medium is a first process. ,
A process in which the second image forming unit forms the second developer image on the transfer medium while the first image forming unit and the transfer medium are separated from each other is a second process. When
A message prompting the replacement of the second image forming unit is displayed on the display unit earlier when the first process is executed than when only the second process is executed. An image forming apparatus. A first image forming unit for forming a first developer image;
A transfer medium onto which the first developer image of the first image forming unit is transferred;
A second image forming unit that is arranged side by side with the first image forming unit in the transport direction of the transfer medium and forms a second developer image;
A display for displaying a message prompting replacement of the second image forming unit;
A control unit,
The controller is
The first image forming unit forms the first developer image and the second image forming unit forms the second developer image as a first image forming process.
When the first image forming unit does not form the first developer image and the second image forming unit forms the second developer image as the second image forming process. ,
A message prompting the replacement of the second image forming unit is earlier when the first image forming process is executed than when only the second image forming process is executed. An image forming apparatus characterized by being displayed on the screen.   The image forming apparatus according to claim 1, wherein the first developer image is made of a developer containing a metal oxide pigment.   The image forming apparatus according to claim 1, wherein the first developer image is made of a white developer. The first image forming unit includes a first image carrier that carries the first developer image on a surface thereof.
The second image forming unit includes a second image carrier that carries the second developer image on a surface thereof.
5. The image forming apparatus according to claim 1, wherein the control unit controls the display unit based on a usage amount of the second image carrier. 6. A counter unit that generates a count value representing the amount of use of the second image forming unit;
A life detecting unit for comparing the count value with a predetermined reference value;
The first image forming unit includes a first image carrier that carries the first developer image on a surface thereof,
The second image forming unit includes a second image carrier that carries the second developer image on a surface thereof.
The counter unit generates the count value with the usage amount of the second image carrier as the usage amount of the second image forming unit;
The image forming apparatus according to claim 1, wherein the life detection unit detects whether or not the second image forming unit has reached the life based on the count value. The first and second image carriers are cylindrical rotating bodies,
The image forming apparatus according to claim 6, wherein the counter unit outputs a value proportional to the number of rotations of each of the first and second image carriers as the count value. The lifetime detector is
8. The image forming apparatus according to claim 6, wherein the cumulative value of the count values is compared with the predetermined reference value to determine whether or not the lifetime has been reached. A counter unit that generates a count value representing the amount of use of the second image forming unit;
A life detecting unit for comparing the count value with a predetermined reference value;
The first image forming unit includes a first image carrier that carries the first developer image on a surface thereof,
The second image forming unit includes a second image carrier that carries the second developer image on a surface thereof.
The counter unit generates the count value with the usage amount of the second image carrier as the usage amount of the second image forming unit;
The lifetime detecting unit detects whether or not the lifetime of the second image forming unit is reached based on the count value;
The counter unit is
When the first developer image is a developer having a structure that wears the surface of the second image carrier, the count value is increased by increasing the count value when performing the first processing. The image forming apparatus according to claim 1, wherein correction is performed. A counter unit that generates a count value representing the amount of use of the second image forming unit;
A life detecting unit for comparing the count value with a predetermined reference value;
The first image forming unit includes a first image carrier that carries the first developer image on a surface thereof,
The second image forming unit includes a second image carrier that carries the second developer image on a surface thereof.
The counter unit generates the count value with the usage amount of the second image carrier as the usage amount of the second image forming unit;
The lifetime detecting unit detects whether or not the lifetime of the second image forming unit is reached based on the count value;
The counter unit is
When the first developer image is a developer having a structure that wears the surface of the second image carrier, the count value is increased by increasing the count value when the first image forming process is performed. The image forming apparatus according to claim 2, wherein the value is corrected. The counter unit is
10. The image forming apparatus according to claim 9, wherein when the first process is performed, the count value is increased by multiplying the count value by a correction coefficient exceeding a value of 1. 11. The counter unit is
11. The image forming apparatus according to claim 10, wherein when the first image forming process is performed, the count value is increased by multiplying the count value by a correction coefficient exceeding a value of 1. A first image forming unit for forming a first developer image;
A transfer medium onto which the first developer image of the first image forming unit is transferred;
A second image forming unit that is arranged side by side with the first image forming unit in the transport direction of the transfer medium and forms a second developer image;
A display for displaying a message prompting replacement of the second image forming unit;
A control unit,
The controller is
A process in which the second image forming unit forms the second developer image on the transfer medium while the first image forming unit is in contact with the transfer medium is a first process. ,
A process in which the second image forming unit forms the second developer image on the transfer medium while the first image forming unit and the transfer medium are separated from each other is a second process. When
A message prompting the replacement of the second image forming unit is displayed on the display unit later when the first process is executed than when only the second process is executed. An image forming apparatus. A first image forming unit for forming a first developer image;
A transfer medium onto which the first developer image of the first image forming unit is transferred;
A second image forming unit that is arranged side by side with the first image forming unit in the transport direction of the transfer medium and forms a second developer image;
A display for displaying a message prompting replacement of the second image forming unit;
A control unit,
The controller is
The first image forming unit forms the first developer image and the second image forming unit forms the second developer image as a first image forming process.
When the first image forming unit does not form the first developer image and the second image forming unit forms the second developer image as the second image forming process. ,
The message prompting the replacement of the second image forming unit is displayed at a later time when the first image forming process is executed than when only the second image forming process is executed. An image forming apparatus characterized by being displayed on a part.   15. The image forming apparatus according to claim 13, wherein the first developer image is made of a transparent developer. A counter unit that generates a count value representing the amount of use of the second image forming unit;
A life detecting unit for comparing the count value with a predetermined reference value;
The first image forming unit includes a first image carrier that carries the first developer image on a surface thereof,
The second image forming unit includes a second image carrier that carries the second developer image on a surface thereof.
The counter unit generates the count value using the amount of use of the second image carrier as the amount of use of the first image forming unit;
The image forming apparatus according to claim 13, wherein the lifetime detection unit detects whether the lifetime of the second image carrier is reached based on the count value. A counter unit that generates a count value representing the amount of use of the second image forming unit;
A life detecting unit for comparing the count value with a predetermined reference value;
The first image forming unit includes a first image carrier that carries the first developer image on a surface thereof,
The second image forming unit includes a second image carrier that carries the second developer image on a surface thereof.
The counter unit generates the count value using the amount of use of the second image carrier as the amount of use of the first image forming unit;
The lifetime detection unit detects whether the second image carrier has reached the lifetime based on the count value,
The counter unit, when performing the first process, reduces the count value by multiplying the count value by a correction coefficient within a range of 0 or more and less than 1. The image forming apparatus described in 1. A counter unit that generates a count value representing the amount of use of the second image forming unit;
A life detecting unit for comparing the count value with a predetermined reference value;
The first image forming unit includes a first image carrier that carries the first developer image on a surface thereof,
The second image forming unit includes a second image carrier that carries the second developer image on a surface thereof.
The counter unit generates the count value using the amount of use of the second image carrier as the amount of use of the first image forming unit;
The lifetime detection unit detects whether the second image carrier has reached the lifetime based on the count value,
The counter unit reduces the count value by multiplying the count value by a correction coefficient within a range of 0 or more and less than 1 when performing the first image forming process. Item 15. The image forming apparatus according to Item 14. A drive mechanism for driving an intermediate transfer belt as the transfer medium to convey the first and second developer images to a secondary transfer position;
A medium transport mechanism for transporting a recording medium to the secondary transfer position;
A secondary transfer portion for transferring the first and second developer images from the transfer medium to the recording medium at the secondary transfer position;
The first image forming unit is disposed to face the transfer medium,
The second image forming unit is disposed on the downstream side of the first image forming unit so as to be opposed to the transfer target medium. 19. Image forming apparatus. A transfer belt for conveying a recording medium as the transfer medium;
A drive mechanism for driving the transfer belt;
The image according to any one of claims 1 to 18, wherein the first image forming unit and the second image forming unit are arranged in parallel to each other so as to face the transfer belt. Forming equipment.   21. The image forming apparatus according to claim 1, further comprising a support mechanism that allows the first image forming unit and the transfer medium to be separated from each other. The first image forming unit includes:
The image forming apparatus according to any one of claims 1 to 21, wherein the image forming apparatus is disposed upstream of the second image forming unit in a direction in which the transfer medium is conveyed.

Images