JP2019139004A - Image formation apparatus - Google Patents

Abstract

To identify information from which a sign of wearing of an end within an image quality guarantee range of at least image holding means is known.SOLUTION: An image formation apparatus comprises: a photoreceptor 21 which has an image quality guarantee range set within an image formable range 210; an electrification device which electrifies at least the image formable range of the photoreceptor 21; a development device which develops an electrostatic latent image formed on the photoreceptor 21 with a developer; control means which performs first image forming operation to develop even ends 215, 216, outside the image quality guarantee range, in the image formable range 210 of the photoreceptor 21 with the developer; and output means which outputs information associated with a result of the first image forming operation. An identification code 100 is added to a recording form to be output.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an image forming apparatus.

  Conventionally, as an image forming apparatus or the like having a function of estimating the cause of occurrence of an abnormal image, for example, those described in Patent Documents 1 to 5 below are known.

  First, in Patent Document 1, a sample image is output as an image that is not output by normal image processing, and the sample image is read by an image input device to determine whether an abnormal image has occurred. There is shown an image forming apparatus in which a sign of occurrence of an abnormal image is found before an abnormality occurs and an action is taken at an early stage. Further, Patent Document 1 exemplifies that the abnormality is that the fixing roller and the pressure roller of the fixing device are deformed and that the photosensitive drum has a lot of moisture.

  Japanese Patent Application Laid-Open No. 2004-228688 calculates an amount of deviation of image data with respect to a normal state, determines whether or not an abnormal state is based on the amount of deviation, and an abnormality that identifies an abnormal location from the state of the image forming apparatus When it is determined that there is an abnormality by the location identification means and the state determination means, and when it is determined that there is an abnormality by the image processing means that performs image processing for abnormality according to the output of the abnormal location identification means and the state determination means 1 shows an image forming apparatus including serviceman call output means for outputting a serviceman call signal.

  Patent Document 3 discloses an image input unit, an image forming unit that forms an output image on a recording medium based on the input image data, a discharge unit that discharges the recording medium on which the image is recorded, and a discharge unit. An image reading unit that outputs a read image obtained by reading the recorded recording medium, an abnormality detection image generation unit that outputs image data for abnormality detection that is likely to generate an abnormal image due to the charging unit of the image forming unit, and the abnormality Comparing means for comparing the output data from the image reading means that has read the recording medium on which the output image is formed based on the detection image data and the input abnormality detection image data, and outputting a determination result; An image forming apparatus having a determination unit capable of detecting the presence or absence of abnormality of the charging unit based on the determination result of the comparison unit is shown.

  Further, in Patent Document 4, a plurality of latent image carriers are provided, a process of transferring an image from each latent image carrier to a transfer body, a failure of an optical sensor and an image forming apparatus directed to the transfer body In the image forming apparatus provided with the failure detection means for performing the prediction, when the occurrence of color streak is predicted, a transfer bias is applied to the transfer body for each latent image carrier and the transfer body is detected by the failure detection means. An image forming apparatus having a mode for detecting the surface state of the image is shown. Patent Document 4 also shows that according to this image forming apparatus, it is possible to specify an image forming unit of a color in which a sign of image failure such as a color streak has occurred.

  Furthermore, Patent Document 5 discloses an image processing apparatus having an image forming unit that forms an image, an acquisition unit that acquires a feature amount from a result of reading a chart formed by the image forming unit, and an acquisition unit that acquires the feature amount. A determination unit that determines whether or not an image formed by the image forming unit includes a defect according to the determined feature amount, and a notification unit that notifies information about a result determined by the determination unit. An image processing apparatus having a determination unit that determines whether to add an image generated from a result of reading a chart to information notified by a notification unit according to a feature amount acquired by the unit is shown.

JP 2004-133081 A JP 2007-334269 A JP 2008-170549 A JP 2008-292773 A JP 2016-46595 A

  SUMMARY OF THE INVENTION An object of the present invention is to make it possible to identify information that knows a sign that at least an end of an image quality guarantee range in an image holding means is worn.

The invention described in claim 1 includes image holding means having an image quality guarantee range within an image formable range;
Charging means for charging at least an image forming range of the image holding means;
Developing means for developing the electrostatic latent image formed on the image holding means with a developer;
Control means for executing a first image forming operation for developing at least an end portion outside the image quality guarantee range of the image holding means of the image holding means with a developer;
Output means for outputting information on the result of the first image forming operation;
Adding means for adding identification information for identifying information related to the result of the first image forming operation;
An image forming apparatus.

According to a second aspect of the present invention, the control unit controls the operation of charging the image forming range of the image holding unit with the charging unit and developing with the developer, and the image forming range of the image holding unit. The second image forming operation including the operation of developing with the developer without being charged by the charging means can be executed,
The image forming apparatus according to claim 1, wherein the adding unit adds the identification information by the second image forming operation.

The invention described in claim 3 is provided with a developing voltage feeding means capable of supplying a developing voltage to the developing means,
The image forming apparatus according to claim 1, wherein the adding unit adds the identification information by switching between supply and non-supply of a development voltage supplied from the development voltage power supply unit or a value of the development voltage.

According to a fourth aspect of the present invention, there is provided transfer means for transferring an image held by the image holding means to an intermediate transfer member or a recording medium;
A transfer voltage feeding means capable of supplying a transfer voltage to the transfer means;
4. The image forming apparatus according to claim 1, wherein the adding unit adds the identification information by switching between supply and non-supply of a transfer voltage supplied from the transfer voltage power supply unit or a value of the transfer voltage. 5. is there.

According to a fifth aspect of the present invention, a plurality of image forming units having the image holding unit, the charging unit, and the developing unit,
With
The image forming apparatus according to claim 1, wherein the adding unit adds identification information using the image forming unit that does not execute the first image forming operation.

  According to the first aspect of the present invention, it is possible to identify information for knowing a sign that at least the end of the image quality guarantee range in the image holding means is worn.

  According to the second aspect of the present invention, identification information can be added to information for knowing abnormality of the charging means.

  According to the third aspect of the present invention, the identification information is simplified compared to the case where the identification information is added without switching the supply or non-supply of the development voltage supplied from the development voltage power supply means or the value of the development voltage. Can be added to.

  According to the fourth aspect of the present invention, the identification information is simplified compared to the case where the identification information is added without switching the supply or non-supply of the transfer voltage supplied from the transfer voltage power supply means or the value of the transfer voltage. Can be added to.

  According to the fifth aspect of the present invention, the image forming unit that does not execute the first image forming operation is used as compared with the case where the identification information is not added using the image forming unit that does not execute the first image forming operation. The identification information can be added by the normal image forming operation.

1 is an explanatory diagram illustrating a configuration of an image forming apparatus according to Embodiment 1 and the like. FIG. 2 is an explanatory diagram illustrating an enlarged configuration of an image forming apparatus in the image forming apparatus of FIG. 1. It is explanatory drawing which shows the structure of each site | part, etc. in a photosensitive drum. It is explanatory drawing which shows the process in which the edge part abrasion in a photosensitive drum shows, (a) shows the relationship between a photosensitive drum and a charging roll, (b) shows the initial state of the partial wear in a photosensitive drum, (c). Indicates a state in which the partial wear of the photosensitive drum is in progress, and (d) indicates a state of occurrence of end wear on the photosensitive drum. (A) is explanatory drawing which shows the electric potential relationship on the photosensitive drum at the time of forming a normal image, (b) is explanatory drawing which shows the electric potential relationship on the photosensitive drum at the time of performing 1st image forming operation | movement. It is explanatory drawing which shows the example of a result output when performing 1st image formation operation | movement. FIG. 2 is an explanatory diagram illustrating a partial configuration of a control system in the image forming apparatus of FIG. 1. It is explanatory drawing which shows the image formed based on the conventional 1st image formation operation | movement. 6 is an explanatory diagram illustrating an image formed based on a first image forming operation in Embodiment 1. FIG. It is explanatory drawing which shows a two-dimensional barcode. 6 is an explanatory diagram illustrating an image formed based on a first image forming operation in Embodiment 1. FIG. 6 is an explanatory diagram illustrating an image formed based on a first image forming operation in Embodiment 1. FIG. (A) is explanatory drawing which shows the electrical potential relationship on a photosensitive drum when performing 2nd image formation operation (first half operation | movement) in the image forming apparatus which concerns on Embodiment 2, (b) is 2nd image formation operation | movement ( FIG. 10 is an explanatory diagram showing a potential relationship on the photosensitive drum when executing the latter half operation). It is explanatory drawing which shows the example of a result output when performing 2nd image forming operation | movement (1st half operation | movement). It is explanatory drawing which shows the example of a result output when performing 2nd image formation operation | movement (second half operation | movement). 5 is an explanatory diagram illustrating a configuration of an image forming apparatus according to Embodiment 3. FIG. 10 is an explanatory diagram illustrating an operation of the image forming apparatus according to Embodiment 3. FIG. 10 is an explanatory diagram illustrating an image formed based on a second image forming operation in Embodiment 3. FIG.

  Hereinafter, modes for carrying out the present invention (hereinafter simply referred to as “embodiments”) will be described with reference to the accompanying drawings.

[Embodiment 1]
1 to 3 show an image forming apparatus 1 according to the first embodiment. FIG. 1 shows the overall configuration of the image forming apparatus 1, FIG. 2 shows the configuration of the image forming apparatus in the image forming apparatus 1, and FIG. 3 shows the configuration of a part of the control system in the image forming apparatus 1. Yes.

<Overall Configuration of Image Forming Apparatus>
The image forming apparatus 1 employs an electrophotographic system, and finally forms an image composed of toner on a recording sheet 9 as an example of a recording medium based on image information including characters, photographs, figures, and the like. is there. As shown in FIG. 1, the image forming apparatus 1 includes a housing 10 having a box-like appearance as a whole. The image forming apparatus 1 includes an image forming device 20 as an example of an image forming unit that forms a toner image composed of toner as a developer in a housing 10, and a toner image formed by the image forming device 20. Is transferred to the secondary transfer position for secondary transfer to the recording paper 9 after being held by primary transfer, and the recording paper 9 supplied to the secondary transfer position of the intermediate transfer device 30 is stored and supplied. A paper device 40 and a fixing device 50 for fixing the toner image secondarily transferred by the intermediate transfer device 30 to the recording paper 9 are disposed. The housing 10 is formed with a support structure portion and an exterior portion using materials such as a support member and an exterior material, for example. A one-dot chain line shown in FIG. 1 is a main conveyance path of the recording paper 9 inside the housing 10.

  Further, the image forming apparatus 1 includes an operation display device 14 having an input unit 14a for inputting instructions, conditions, and the like regarding the operation of the image forming apparatus 1 and a display unit 14b for displaying various information such as the conditions and states of the operation. A central control device 60 and the like for controlling the overall operation of the image forming apparatus 1 (the above-described devices and the like) are also arranged.

  As will be described later, the image forming apparatus 1 according to the first embodiment has a function of knowing a sign of abnormality related to at least some of the components. Further, the image forming apparatus 1 also has a function of making it possible to identify a plurality of pieces of information for knowing signs of abnormality related to at least some of the components.

  The image forming apparatus 20 includes four image forming apparatuses 20Y, 20M, 20M, 20M, 20M, 20M, 20M, 20M, 20M, and 20D respectively forming developer (toner) images of four colors of yellow (Y), magenta (M), cyan (C), and black (K). 20C and 20K are used. As shown in FIGS. 1 and 2, each of the image forming devices 20 (Y, M, C, and K) is a photosensitive drum 21 as an example of an image holding unit that is rotationally driven in a direction indicated by an arrow A. Each is equipped. Around each photosensitive drum 21, a charging device 22 as an example of a charging unit, an exposure device 23 as an example of an electrostatic latent image forming unit, a developing device 24 as an example of a developing unit, and an example of a primary transfer unit A primary transfer device 25, a drum cleaning device 26, a static eliminator 27, and the like are arranged.

  For example, the photosensitive drum 21 forms an image forming surface (image forming range) having a photodielectric layer (photosensitive layer) made of a photosensitive material on the peripheral surface of a cylindrical or columnar conductive base material to be grounded. This is a drum-shaped photoconductor. The photosensitive drum 21 is provided so as to be rotationally driven in a direction indicated by an arrow A by receiving power from a rotation driving device (not shown).

  The charging device 22 is, for example, a contact-type charging device including a charging roll 221 that is arranged in contact with the image forming surface of the photosensitive drum 21 and is driven to rotate and to which a required negative charging bias is supplied. It is. As shown in FIG. 2, the charging roll 221 is configured by covering an outer periphery of a rotating shaft 223 made of a columnar metal with a conductive elastic layer 224. As shown in FIG. 3, the charging roll 221 can be driven to rotate in a state where both end portions along the axial direction of the rotating shaft 223 are in pressure contact with the surface of the photosensitive drum 21 by receiving a required pressure F. It is supported. The charging device 22 is not limited to a contact type charging device, and a non-contact type charging device such as a scorotron may be used.

  The exposure apparatus 23 is, for example, a non-scanning exposure apparatus configured using light emitting diodes and optical components, or a scanning exposure apparatus configured using optical components such as a semiconductor laser and a polygon mirror. is there. The exposure device 23 receives image information input from the outside through a communication means, a reading device, etc., and image information stored in an internal storage unit after each image component (not shown) has undergone a required process, and each color component ( Y, M, C, and K) are input as image signals that have been decomposed. The exposure device 23 performs exposure according to the input image signal.

  The developing device 24 is, for example, a developing device 24 (Y, M, C, K) that uses a two-component developer including toner of any one of the four colors (Y, M, C, K) and a magnetic carrier. It is. Further, the developing device 24 (Y, M, C, K) is used, for example, to perform reversal development by charging the toner to a negative polarity. Further, as shown in FIG. 2, the developing device 24 (Y, M, C, K) holds the two-component developer accommodated in the housing and conveys it to the developing area facing the photosensitive drum 21. A developing roll 241 or the like as an example of a developer holder that rotates so as to rotate is provided. For example, a developing bias in which an AC component is superimposed on a DC component is supplied to the developing roll 241 between the photosensitive drum 21 and the developing roll 241.

  For example, the primary transfer device 25 is disposed so as to contact and rotate (following an intermediate transfer belt 31 described later) on an image forming surface portion as a primary transfer position of the photosensitive drum 21 and to perform a required primary rotation. This is a contact type transfer device including a primary transfer roll to which a transfer bias is supplied.

  The drum cleaning device 26 is disposed so as to contact at least the image forming surface portion after the primary transfer of the photosensitive drum 21 in the cleaning work opening of the housing, and removes unnecessary materials such as residual toner on the image forming surface. It includes a cleaning member such as an elastic plate that is scraped off and removed.

  The static eliminator 27 neutralizes the surface potential by, for example, neutralizing the image forming surface of the photosensitive drum 21 by exposure or the like.

  The intermediate transfer device 30 is disposed at a position below the four image forming devices 20 (Y, M, C, K). The intermediate transfer device 30 is arranged to rotate in the direction indicated by the arrow B while passing through the primary transfer position facing the primary transfer device 25 of the photosensitive drum 21 in the image forming device 20 (Y, M, C, K). An intermediate transfer belt 31 is provided as an example of the intermediate transfer means.

  The intermediate transfer belt 31 is formed into an endless belt shape having a required thickness and electric resistance value using a material in which a resistance adjusting agent such as carbon is dispersed in a base material such as polyimide resin or polyamide resin. is there.

  The intermediate transfer belt 31 is supported around a plurality of support rolls 32a to 32e so as to be rotatable. The support roll 32a is a drive roll, the support roll 32b is a driven roll that holds the primary transfer surface in cooperation with the drive roll 32a, and the support roll 32c applies tension to the intermediate transfer belt 31 and meanders the intermediate transfer belt 31. The support roll 32d is configured as a secondary transfer backup roll, and the support roll 32e is configured as a cleaning backup roll.

  The intermediate transfer device 30 includes a secondary transfer device 35 as an example of a secondary transfer unit that secondarily transfers the toner image transferred onto the intermediate transfer belt 31 to the recording paper 9, and an outer peripheral surface of the intermediate transfer belt 31. And a belt cleaning device 36 for removing unnecessary substances such as toner adhering to the image holding surface.

  The secondary transfer device 35 includes, for example, a contact member such as a secondary transfer roll disposed so as to contact and rotate the image holding surface portion supported by the secondary transfer backup roll 32d of the intermediate transfer belt 31. A contact type transfer device is employed. In the secondary transfer device 35, a contact member such as a secondary transfer roll is grounded, and the secondary transfer backup roll 32d has a required secondary transfer bias having a negative polarity that is the same as the charging polarity of the toner. Supplied.

  The belt cleaning device 36 is disposed in contact with at least the image holding surface portion after the secondary transfer of the intermediate transfer belt 31 in the cleaning work opening of the housing, and an unnecessary object such as residual toner on the image holding surface. A cleaning member such as an elastic plate for scraping off and cleaning is provided.

  The paper feeding device 40 is arranged at a position below the intermediate transfer device 30. The sheet feeding device 40 is detachably attached to the housing 10 and accommodates a recording body 9 in which recording sheets 9 having a desired size and type are stacked on a stacking plate (not shown), A delivery device 42 is provided for feeding the recording paper 9 from the container 41 one by one toward the paper feed path. The number of containers 41 and delivery devices 42 is increased or decreased as necessary. Further, the sheet feeding device 40 supplies the recording paper 9 from a sheet feeding tray (not shown) used in the state opened to the outside of the housing 10 so as to join a middle portion of a supply conveyance path (Rt1) described later. A paper feed mechanism is provided.

  The recording paper 9 can be applied as long as it can be transported by a transport path in the housing 10 and can transfer and fix a toner image. As the recording sheet 9, for example, a recording sheet cut into a predetermined size, a thick sheet such as a postcard, and a special medium such as an envelope can be used.

  The fixing device 50 is disposed at a position below the intermediate transfer device 30. The fixing device 50 includes a heating unit configured to rotate in a direction indicated by an arrow and to maintain a surface temperature at a predetermined temperature inside a housing 51 in which an introduction port 51a and a discharge port 51b of the recording paper 9 are formed. The heating rotator 52 in the form of a roll or a belt heated by the heating member 52 and the heating rotator 52 in the form of a roll or belt that rotates in contact with a predetermined pressure in a state substantially along the axial direction of the heating rotator 52. A pressure rotating body 53 is installed. In the fixing device 50, a portion where the heating rotator 52 and the pressing rotator 53 come into contact with each other serves as a fixing processing unit in which the recording paper 9 holding the toner image is introduced and fixing processing (heating and pressing) is performed. It is configured.

  Further, in the image forming apparatus 1, as a main sheet conveyance path inside the housing 10, a supply conveyance path Rt 1 that connects between the sheet feeding apparatus 40 and the intermediate transfer apparatus 30 and a secondary transfer of the intermediate transfer apparatus 30. A relay conveyance path Rt2 that connects between the position and the fixing device 50, a discharge conveyance path Rt3 that connects between the fixing device 50 and the sheet discharge port 11 of the housing 10, and a branch from the middle of the discharge conveyance path Rt3. The reversal conveyance path Rt4 for reversing the front and back of the recording paper 9 and the double-sided conveyance path Rt5 for conveying the recording paper 9 branched from the upper side of the reversal conveyance path Rt4 to the side and reversed front and back to the supply conveyance path Rt1. Is provided.

  The supply conveyance path Rt1 is a conveyance path that conveys and supplies the recording paper 9 delivered from the paper feeding device 40 to the secondary transfer position of the intermediate transfer device 30. The supply conveyance path Rt1 includes a plurality of sheet conveyance roll pairs 45a to 45d and a plurality of sheet guide members (not shown). The relay conveyance path Rt2 is a conveyance path for conveying the recording sheet 9 after the secondary transfer to the fixing device 50. The relay conveyance path Rt2 is configured by, for example, an intake belt conveyance device 46. The discharge conveyance path Rt3 is a conveyance path for conveying the recording paper 9 on which an image has been formed after fixing to the discharge container 12. The discharge conveyance path Rt3 includes a plurality of discharge roll pairs 47a, 47b and the like and a sheet guide member (not shown). The reverse conveyance path Rt4 includes a reverse roll pair 48 whose rotation direction can be switched between a normal rotation direction and a reverse rotation direction, and a sheet guide member (not shown). The reverse conveyance path Rt4 is a conveyance path in which the conveyance direction of the recording paper 9 is switched from the discharge conveyance path Rt3 by a switching member (not shown). The double-sided conveyance path Rt5 includes a plurality of sheet conveyance roll pairs 49 and the like, a plurality of sheet guide members (not shown), and the like.

<Basic Image Forming Operation by Image Forming Apparatus>
In the image forming apparatus 1, a basic image forming operation described below is performed. Here, an operation in the case of forming a full-color image configured by combining toner images of four colors (Y, M, C, K) will be described as an example.

  First, in the image forming apparatus 1, when the central controller 60 receives a request command for an image forming operation from the outside or the like, in each of the four image forming apparatuses 20 (Y, M, C, and K), each photosensitive drum 21 is moved to an arrow. Each of the charging devices 22 is rotated in the direction indicated by A and receives a supply of charging current to generate contact discharge. As a result, the image forming surface of each photosensitive drum 21 is charged to a required polarity (for example, negative polarity) and potential.

  Subsequently, each exposure device 23 performs exposure according to the image signal separated into each color component (Y, M, C, K) on the image forming surface of each photosensitive drum 21 after charging. Thereby, an electrostatic latent image of each color component having a predetermined potential is formed on the image forming surface of each photosensitive drum 21.

  Subsequently, each developing device 24 (Y, M, C, K) supplies toner of a color (Y, M, C, K) charged to a predetermined polarity (minus polarity) from the developing roll 241. The electrostatic latent image of each color component on the image forming surface of the photosensitive drum 21 is electrostatically applied to the portion of the image forming surface of the photosensitive drum 21 by a developing electric field formed between the developing roll 241 and the photosensitive drum 21 in response to the supply of the developing bias. Adhere. As a result, toner images of corresponding colors among the four colors (Y, M, C, K) are individually formed on the image forming surface of each photosensitive drum 21.

  Subsequently, each primary transfer device 25 is supplied with a primary transfer current to form a primary transfer electric field between the primary transfer device 25 and the photosensitive drum 21, thereby transferring the toner image on each photosensitive drum 21 to the intermediate transfer device 30. Primary transfer is performed in order (Y, M, C, K) on the image holding surface of the transfer belt 31. Further, the drum cleaning device 26 cleans the image forming surface of each photosensitive drum 21 after the primary transfer or the like. Further, the static eliminator 27 neutralizes the image forming surface of each photoconductive drum 21 after the primary transfer or the like to prepare for the next image forming operation on each photoconductive drum 21.

  Next, in the intermediate transfer device 30, the intermediate transfer belt 31 rotates in the direction indicated by the arrow B, whereby the unfixed toner image that is primarily transferred and held on the image holding surface faces the secondary transfer device 35. Transport to the next transfer position. On the other hand, in the paper feeding device 40, the delivery device 42 sends the required recording paper 9 from the container 41 to the supply conveyance path Rt 1, and then sends it to the secondary transfer position of the intermediate transfer device 30 via the supply conveyance path Rt 1. To supply. At the secondary transfer position, the secondary transfer device 35 receives the supply of the secondary transfer bias and forms a secondary transfer electric field between the secondary transfer device 35 and the four colors on the intermediate transfer belt 31. The toner image is secondarily transferred to one side of the recording paper 9.

  Next, the recording sheet 9 on which the unfixed toner image is secondarily transferred is separated from the intermediate transfer belt 31 and then conveyed so as to be sent to the fixing device 50 via the relay conveyance path Rt2. In the fixing device 50, the recording paper 9 is heated and pressurized when it is introduced into and passed through the fixing processing unit which is a contact portion between the heating rotator 52 and the pressing rotator 53. As a result, the toner constituting the toner image is melted under pressure, and the toner image is fixed on the recording paper 9.

  Subsequently, the recording paper 9 on which the toner image is fixed is discharged from the inside of the casing 51 of the fixing device 50 and then conveyed via the discharge conveyance path Rt3. Are discharged outside and stored in the discharge storage portion 12.

  Further, when images are formed on both sides of the recording paper 9, the recording paper 9 having an image formed on one side is not discharged to the discharge accommodating portion 12, but is discharged from the discharge conveyance path Rt3 to the reverse conveyance path Rt4 by a switching member (not shown). Transport to. The reversing roll pair 48 in the reversing conveyance path Rt4 changes the rotation direction from the normal rotation direction to the reverse rotation direction while holding the upper end of the conveyed recording paper 9, and the recording paper 9 is reversed in the reversed state. Is conveyed to the double-sided conveyance path Rt5. The recording sheet 9 conveyed to the double-sided conveyance path Rt5 has the toner image transferred to the back surface via the supply conveyance path Rt1. Thereafter, the recording paper 9 is transported to the fixing device 50 via the relay transport path Rt2, subjected to fixing processing (heating and pressurization) by the fixing device 50, and discharged to the discharge accommodating portion 12 via the discharge transport path Rt3. Is housed in.

  By performing the above operation, one recording sheet 9 on which a full-color image is formed on one side or both sides is output. When a request command for a plurality of image forming operations is received, the image forming operation is repeated in the same manner for the number of sheets.

  In addition, the image forming apparatus 1 forms a monochrome image by operating any one of the four image forming apparatuses 20 (Y, M, C, K) in the image forming operation. It is also possible to form a color image other than a full-color image by operating two or three of the image forming devices 20 (Y, M, C, K) in combination.

<Configuration of Characteristic Part of Image Forming Apparatus>
By the way, the image forming apparatus 1 according to the first embodiment has the following configuration as a function for knowing a sign of abnormality such as at least wear of the end of the image quality guarantee range in the photosensitive drum 21. . Further, the image forming apparatus 1 has the following configuration as a function for identifying a plurality of pieces of information for knowing a sign of abnormality such as at least the end of the image quality guarantee range of the photosensitive drum 21 being worn. Yes.

  The photosensitive drum 21 has an image quality guarantee range 212 as shown in FIG. Here, the image quality guarantee range 212 is larger than the width of the maximum size recording sheet 9 (for example, the width in the short direction of A3 size) among the sheets that are allowed to form an image by the user in the image forming apparatus 1. The image quality guarantee range 212 is an area used to form a normal image (including a borderless image) instructed to the image forming apparatus 1 by the user. Further, the photosensitive drum 21 is configured as an image formable range 210 including the end portions 215 and 216 positioned at both ends on the outer side along the axial direction D of the image quality guarantee range 212. The end portions 215 and 216 of the photosensitive drum 21 have a photosensitive layer made of a photosensitive material on the peripheral surface of the conductive substrate. The image formable range 210 of the photosensitive drum 21 is literally a range in which image formation is possible. However, no image is formed on the end portions 215 and 216 of the photosensitive drum 21 during normal image formation.

  As described above, the image formable range 210 of the photoconductive drum 21 is a range excluding the left and right end portions (image non-formable portions) in the axial direction D of the photoconductive drum 21, as shown in FIG. More specifically, it is a part of the image forming surface of the photoconductor drum 21 on which the photoconductor layer is formed, and is within a range in which an image forming operation can be performed by charging, exposure (latent image formation) and development processes. . The range in which the developer is held on the developing roll 241 and development is possible (developable range) is substantially the same as the image formable range 210 of the photosensitive drum 21 in the axial direction D. Further, the image formed in the image formable range 210 of the photosensitive drum 21 is transferred to the intermediate transfer belt 31 by the primary transfer device 25, and secondly from the intermediate transfer belt 31 to the recording paper 9 by the secondary transfer device 35. Next transfer is possible.

  By the way, the photosensitive drum 21 is charged when the charging roll 221 of the charging device 22 contacts as shown in FIG. As described above, the charging device 22 is supported in a state where the rotating shaft 223 of the charging roll 221 receives the applied pressure F at both ends in the axial direction D. The charging roll 221 in such a support state has a convex shape that faces upward from the outer peripheral surface of the photosensitive drum 21 at the center thereof and toward the direction of approaching the photosensitive drum 21 at both ends thereof. To be bent and bent. For this reason, the photosensitive drum 21 is placed in a state in which the left and right ends of the charging roll 221 are kept in contact with a relatively strong pressure compared to the central portion.

  As a result, as shown in FIGS. 4A and 4B, the photosensitive drum 21 has a portion where the left and right ends of the charging roll 221 are in strong contact (usually, the outer portion of the image forming range 210). The part where the pressure contact force is locally increased starts to be worn in a streak shape so as to extend in the circumferential direction (reference numeral 219 is a worn part). In addition, as the usage frequency of the photosensitive drum 21 increases, the stripe-shaped wear portion 219 has an inner side (center portion) along the axial direction D as illustrated in FIGS. 4C and 4D in order. It gradually displaces so as to enter, and it becomes unevenly worn.

  That is, the worn portion 219 generated on the photosensitive drum 21 enters the end portions 215 and 216 located outside the image quality guarantee range 212 of the image formable range 210 as shown in FIG. grow up. Thereafter, as shown in FIG. 4D, the worn portion 219 grows until it enters the image quality guarantee range 212 located inside from one or both of the left and right end portions of the image quality guarantee range 212.

  In this case, the stage where the wear portion 219 enters the left and right end portions of the image quality guarantee range 212 is a situation where the end portion wear in the photosensitive drum 21 at the time of occurrence of abnormality occurs. Further, the growth rate and the extent of expansion of the friction portion 219 may occur evenly at the left and right end portions of the photosensitive drum 21, but may differ at the left and right end portions.

  The photoconductive drum 21 is formed by forming a photoconductive layer on the peripheral surface of a grounded conductive base material, and functions as a capacitor to which the surface of the photoconductive layer is charged by a charging roll 221 and charged. . When the photoconductor layer of the photoconductor drum 21 is worn and the film thickness is reduced, the distance between the peripheral surface of the conductive base material of the photoconductor drum 21 and the surface of the photodielectric layer is reduced, and the photoconductor drum functioning as a capacitor. The electrostatic capacity C (= Q / V) of 21 decreases locally. Therefore, if there is a wear portion 219 in at least the image formable range 210 of the photosensitive drum 21, the same charge Q is applied by the charging roll 221 due to a decrease in the capacitance C accompanying a decrease in the film thickness of the photosensitive layer. Even so, the level of dark attenuation that decreases until the surface potential V of the photosensitive drum 21 moves to the developing position facing the developing roll 241 of the developing device 24 increases. In the photosensitive drum 21, the rate at which the charging potential: Vh of the photosensitive drum 21 decreases corresponding to the increase in the level of dark attenuation increases. As a result, the wear portion 219 is made to adhere more toner in the development process, and is visualized as a portion having a higher density than portions other than the wear portion 219.

  More specifically, in the image forming apparatus 1, as shown in FIG. 5A, the developing potential Vd1 of the developing roller 241 of the developing device 24 is lower than the charging potential Vh1 of the photosensitive drum 21 during normal image formation. The image area whose charging potential is reduced to Vi by image exposure is reversely developed with toner supplied from the developing roll 241.

  On the other hand, in the image forming apparatus 1, as shown in FIG. 5B, in order to detect the presence / absence of the worn portion 219 of the photosensitive drum 21, the photosensitive drum 21 is placed on the developing roll 241 of the developing device 24. A developing potential Vd2 higher than the charging potential Vh1 is supplied. Then, when the wear portions 219 exist at the end portions 215 and 216 of the photoconductor drum 21, as described above, the charging potential Vh1 ′ of the photoconductor drum 21 is lower than that in the region where the other wear portions 219 are not generated. To do. Therefore, the wear portion 219 of the photoconductive drum 21 has a potential difference (Δα1) between the charging potential Vh1 ′ of the photoconductive drum 21 and the development potential Vd2 of the developing roll 241 compared to a region where no other wear portions 219 are generated. ) Becomes larger and is visualized as a portion having a higher density than portions other than the worn portion 219.

  In the image forming apparatus 1, the dark image portions K 1 and K 2 in which the developed image where the wear portion 219 is developed in a dark eye can be seen as a streak are aligned along the axial direction of the image quality guarantee range 212 as shown in FIG. Appears outside. Therefore, in order to transfer and detect on the recording paper 9 the dark image portions K1 and K2 that appear as streaks near the left and right end portions along the axial direction of the photosensitive drum 21, they are normally used as the recording paper 9. Therefore, it is necessary to use a special recording sheet 9B having a wider width along the axial direction of the photosensitive drum 21 than a standard recording sheet 9 such as A3 size. The left and right end portions of the special recording sheet 9B correspond to the end portions 215 and 216 outside the image quality guarantee range of the photosensitive drum 21. As the special recording sheet 9B, a sheet having a wider width than the end portions 215 and 216 outside the image quality guarantee range of the photosensitive drum 21 may be used.

  In the image forming apparatus 1, by performing the first image forming operation in which no image exposure is performed on the special recording paper 9B, a sign of abnormality such as wear of the end of the image quality guarantee range in the photosensitive drum 21 is known. It becomes possible. In the first image forming operation, if there are dark image portions K1 and K2 that look like streaks at the left and right ends of the special recording paper 9B, the wear portions before the end that develop into the original end wear Since this indicates that 219 is generated on the photosensitive drum 21, the presence of the image portions K1 and K2 can be regarded as a sign of an abnormality such as end wear.

  As described above, when end wear occurs in the image quality guarantee range 212 of the photosensitive drum 21, when a normal image is formed, a streak-like image defect due to the end wear occurs. However, by performing the first image forming operation and examining the result, it is possible to know a sign of an abnormality such as end wear in the photosensitive drum 21 before the image defect occurs.

  Therefore, in the image forming apparatus 1 according to the first embodiment, as shown in FIG. 6, the developed image of the worn portion 219 is dark in the vicinity of the left and right end portions of the special recording paper 9B. The first image forming operation is performed to output the images so as to appear as dark image portions K1 and K2 having a high density.

  That is, as shown in FIG. 7, the image forming apparatus 1 develops the end portions 215 and 216 that are at least outside the image quality guarantee range 212 in the image formable range 210 of the photosensitive drum 21 with the developer. A control unit 61 that executes an image forming operation and an output unit 70 that outputs information about the result of the first image forming operation are provided.

  The control means 61 is executed by a CPU (Central Processing Unit) 61a that comprehensively controls the operation of the image forming apparatus 1, a ROM (Read Only Memory) 61b that stores programs executed by the CPU 61a, and the CPU 61a. A RAM (Random Access Memory) 61c that stores parameters used in the program and a bus (not shown) that connects the CPU 61a, ROM 61b, and the like are provided. The control means 61 is configured to perform the first image forming operation described above by executing a program stored in the ROM 61b. The control means 61 executes the first image forming operation, and also executes an operation of sequentially storing the image forming conditions and the result of the first image forming operation when the first image forming operation is executed in the ROM 61b. The control means 61 has a timekeeping function and a calendar function. Each time the first image forming operation is executed, the control means 61 adds and stores date and time information to the image forming conditions and the result of the first image forming operation. Also, it has a function of appropriately reading out the past conditions and results of the first image forming operation and displaying them on the display unit 14b of the operation display device 14. The control unit 61 is configured as a part of the central controller 60, but may be configured as an independent control unit.

  The control unit 61 may include a detection unit such as an environmental sensor (not shown) that detects at least one of temperature and humidity installed in the image forming apparatus 1. This is particularly effective when the characteristics of the photoconductor drum 21 have environmental dependencies such as temperature and humidity.

  As shown in FIG. 7, the control unit 61 supplies a charging bias to the charging roll 221 of the charging device 22 and also supplies a charging voltage to the developing roll 241 of the developing device 24 and a developing voltage. The power supply unit 15 is connected to the power supply unit 15 as an example of the power supply unit, the exposure driving unit 16 that drives the exposure device 23, the output unit 70 that outputs the result of the first image forming operation, the display unit 14b of the operation display device 14, and the like. Control signals necessary for performing the first image forming operation and the like are transmitted to them. The control means 61 is connected to the communication unit 19 for communicating information with an external device or the like, the input unit 14a of the operation display device 14, and the like, thereby obtaining information necessary for the control operation. ing.

  When the control unit 61 executes the first image forming operation, the end portions 215 and 216 that are out of the image quality guarantee range of the photosensitive drum 21 with respect to at least one of the charging bias and the developing bias supplied from the power supply unit 15. Also, the condition for generating the potential difference Δα that can be developed with the developer (toner) supplied from the developing device 24 is changed over a plurality of stages.

  The first image forming operation at this time is a developing operation in which the toner is uniformly attached to the entire image forming range 210 of the photosensitive drum 21. The first image forming operation also includes a developing operation by a so-called fog phenomenon in which toner is uniformly attached to the entire image forming range 210. In addition, when there are a plurality of image forming apparatuses 20 including the photosensitive drum 21 and the charging device 22, the first image forming operation is performed by one of the plurality of image forming apparatuses 20 (Y, M, C, K). It is done sequentially while operating each one. Further, the image forming apparatus 20 (Y, M, C, K) that may cause an abnormality is frequently executed as compared with a specific image forming apparatus, for example, an image forming operation. When the image forming device is limited to the black (K) image forming device 20K or the like, the first image forming operation may be executed only by the corresponding image forming device 20.

  Further, when executing the first image forming operation, the control unit 61 controls the operation of the exposure driving unit 16 so that the exposure by the exposure device 23 is not performed and the electrostatic latent image is not formed.

  As shown in FIG. 5B, the potential difference Δα is the development generated by the charging (surface) potential: Vh of the photosensitive drum 21 and the DC component of the developing bias when the end portions 215 and 216 can also be developed. Potential: a difference (absolute value) from Vd (Δα = | Vh−Vd |).

  Actually, this potential difference Δα is based on the charging potential Vh1 (FIG. 5A) when creating a normal image as a reference, and the development potential Vd1 when creating a normal image is set to the end portion 215. It is generated by changing to a special development potential Vd2 (FIG. 5B) when development at 216 is also possible. Further, as the special development potential Vd2 at this time, as shown in FIG. 5B, for example, a potential having a magnitude exceeding the absolute value of the charging potential Vh1 when a normal image is formed. Adopted. This special development potential: Vd2 is obtained in advance by, for example, conducting an experiment for examining a development potential suitable for performing the development by variously changing the development bias (actually the voltage of the DC component).

  Further, the charging potential: Vh1 and the developing potential: Vd2 are such that at least one potential is set to a plurality of values by controlling the power feeding unit 15 based on a signal from the control unit 61 when the first image forming operation is performed. It can be changed.

  As shown in FIG. 5B, for example, when the charging potential: Vh of the photosensitive drum 21 is constant, the control unit 61 sets the developing potential: Vd generated by the DC component of the developing bias in a plurality of stages. Change to a large value over time. When the difference (absolute value) Δα = | Vh−Vd | between the charging (surface) potential of the photosensitive drum 21: Vh and the developing potential: Vd generated by the DC component of the developing bias is small, the photosensitive drum 21 is worn. Even when the first image forming operation is executed, for example, when the wear amount of the portion 219 is small, dark image portions K1, K2 that appear to be streak-like in the vicinity of the left and right end portions of the special recording paper 9B may not appear. . In this case, by increasing the difference (absolute value) Δα = | Vh−Vd | between the charging (surface) potential of the photosensitive drum 21: Vh and the developing potential: Vd generated by the DC component of the developing bias, Even when the wear amount of the wear portion 219 of the body drum 21 is small, development can be performed so that the dark image portions K1 and K2 appear on the special recording paper 9B.

  Further, the first image forming operation by the control means 61 is executed, for example, when a service engineer (service man) selects and instructs the execution mode of the first image forming operation from the input unit 14a in the operation display device 14. It is configured as follows. The service engineer can appropriately set at least one of the charging potential: Vh1 and the developing potential: Vd2 to a desired value by operating the input unit 14a in the operation display device 14.

  In this case, the execution mode of the first image forming operation is displayed as a selection instruction screen on the display unit 14b of the operation display device 14, for example. Further, it is preferable that the execution of the first image forming operation according to the instruction of the service engineer is periodically performed according to the usage frequency progress state based on information such as the number of image formations.

  The output means 70 is configured to transfer (record) and output the developer image (unfixed toner image) formed on the photosensitive drum 21 by the first image forming operation onto a special recording sheet 9B, for example. Has been.

  The output unit 70 configured as described above is an image forming operation for forming a normal image except for changing the developing bias and not forming an electrostatic latent image in the first image forming operation executed by the control unit 61. This is realized by setting the control content to be performed according to the conditions in (1). In the output means 70 having such a configuration, information relating to the result of the first image forming operation is recorded on the recording paper 9 and output.

  However, the recording paper 9 used at the time of output of the output means 70 must be capable of transferring a toner image formed by development on the end portions 215 and 216 outside the image quality guarantee range of the photosensitive drum 21. Therefore, a special recording paper (B for confirmation) 9B which is treated as an exception and whose feed width is substantially the same as the axial dimension of the image formable range 210 on the photosensitive drum 21 is used (FIG. 5). 6).

  The special recording paper 9B is sent out from the paper feeding device 40 to the secondary transfer position of the intermediate transfer device 30 when it can be stored in the container 41 in the paper feeding device 40 and sent out by the feeding device 42. Supplied. On the other hand, if the special recording paper 9B cannot be supplied from the paper supply device 40, for example, the special recording paper 9B is stored in a manual tray in a manual paper supply mechanism (not shown) and then sent out to be joined in the middle of the supply conveyance path Rt1. It is supplied to the secondary transfer position of the transfer device 30.

The first image forming operation is executed by the control means 61 a plurality of n times (n = about 4 to 5) with different values of at least one of the charging potential: Vh1 and the developing potential: Vd2. In the image forming apparatus 1, as shown in FIG. 8, a plurality of special recording sheets 9B ₁ and 9B _{2 to} 9B _n are output by executing the first image forming operation.

However, an image is formed on the plurality of special recording sheets 9B ₁ and 9B _{2 to} 9B _n output from the image forming apparatus 1 without performing the exposure process by the exposure apparatus 23. For this reason, information for identifying each other is not added to a plurality of special recording sheets 9B ₁ and 9B _{2 to} 9B _n output under different conditions, and can be distinguished from each other by themselves. Therefore, there is a management inconvenience.

  Therefore, in the image forming apparatus 1 according to the first embodiment, as shown in FIG. 9, an identification code 100 as an example of identification information for identifying information related to the result of the first image forming operation is used as a special recording sheet 9B. It is comprised so that the addition means to add to may be provided. As the adding means, output means 70 is used. The output unit 70 includes, for example, any one of the four image forming devices 20 (Y, M, C, K).

  In the image forming apparatus 1 according to this embodiment, for example, in an image forming apparatus other than the image forming apparatus 20 that executes the first image forming operation, a normal image forming operation is executed by the control unit 61 to create a plurality of special images. An image having an identification code 100 for identifying different recording sheets 9B from each other is created and added. When the image forming device 20 that executes the first image forming operation is the black (K) image forming device 20K, the image forming device that generates the identification code 100 is an image forming device other than black (K), for example, cyan. The image forming apparatus 20C in (C) is selected. When the image forming device 20 that performs the first image forming operation is the yellow (Y) image forming device 20Y on the most upstream side along the moving direction of the intermediate transfer belt 31, basically, the yellow image forming device 20Y The identification code 100 is created by an imaging device other than the imaging device 20Y of (Y). However, the identification code 100 formed by the image forming device 20 (M, C, K) other than yellow (Y) is transferred to the lower side of the image formed by the first image forming operation of the recording paper 9. Interpretation may be difficult. Therefore, when the first image forming operation is executed by the yellow (Y) image forming apparatus 20Y, the margin 101 is formed at the leading end or the trailing end of the recording paper 9, as shown in FIGS. It is desirable to control the start end or the end end of the first image forming operation so as to form.

  When the first image forming operation is executed by varying at least one of the charging potential: Vh1 and the developing potential: Vd2, the control unit 61 performs identification in the image forming device 20 that does not execute the first image forming operation. An image of reference numeral 100 is created and formed on a corresponding special recording sheet 9B. The image information of the identification code 100 is created by the control means 61.

  Examples of the identification code 100 include various ones as long as a plurality of special recording sheets 9B can be distinguished from each other, such as a one-dimensional barcode, a two-dimensional barcode, or a code that can be visually read such as numerals and characters. Things can be used. In the illustrated embodiment, a two-dimensional bar code is used as the identification code 100 as shown in FIG. Further, as shown in FIG. 11C, the identification code 100 may include a plurality of codes made up of numbers and characters such as Sample 1 and Sample 2 together with the two-dimensional barcode. QR code (registered trademark) as an example of a two-dimensional bar code has an information amount of up to 7,089 characters in numbers only, up to 4,296 characters in alphanumeric characters, and up to 1,817 characters in kanji and kana characters. doing.

  The identification information formed in the identification code 100 includes a charging potential Vh1 of the photosensitive drum 21 that forms an image on a special recording paper 9B, a developing potential Vd2 of the developing device 24, a primary transfer potential, and a secondary transfer potential. Image forming conditions such as, an identification number for individually identifying the image forming apparatus 1, environmental conditions such as temperature and humidity in the image forming apparatus 1 during image formation, and the like.

  The position where the identification code 100 is formed is set in a predetermined specific area of the special recording paper 9B. As the specific region, the same surface as the surface on which an image is formed by the first image forming operation or a surface different from the surface on which an image is formed by the first image forming operation is selected. When the same surface as the surface on which an image is formed is selected as the specific region by the first image forming operation, for example, the specific region is set at a location where the dark image portions K1 and K2 that appear to be a streak-like shape do not appear. The Image portions K1 and K2 having a high stripe density tend to appear at both end portions 215 and 216 other than the image quality guarantee range 212 along the axial direction of the photosensitive drum 21. For this reason, it is desirable to set the specific area within the image quality guarantee range 212 of the photosensitive drum 21.

  Further, the control means 61 has information related to the result when the first image forming operation has been executed previously in the ROM 61b. For this reason, the control means 61 refers to the information related to the result when the first image forming operation was executed before stored in the ROM 61b, so that the presence or absence of the dark image portions K1 and K2 is generated and the darkness is high. Information on the locations where the image portions K1 and K2 have occurred can be acquired. The control means 61 acquires information on the locations where the dark image portions K1 and K2 are generated, so that the dark image portions K1 and K2 that are desired to be detected are not present even outside the image quality guarantee range 212. An identification code 100 is formed.

  Further, the surface different from the surface on which the image is formed by the first image forming operation is special when the surface on which the image is formed by the first image forming operation is the first surface (surface) as shown in FIG. This is the second surface (back surface) of a simple recording sheet 9B. When the second surface (back surface) of the special recording paper 9B is selected as the position for forming the identification code 100, an image is formed on the front surface of the special recording paper 9B by the first image forming operation. An image having the identification code 100 is formed on the back surface of the recording paper 9B. In this case, images are formed on both sides of the special recording sheet 9B. When the identification code 100 is formed on a surface different from the surface on which an image is formed by the first image forming operation, the image forming device that forms the identification code 100 is an image forming device other than the image forming device that executes the first image forming operation. However, it can be arbitrarily selected. As the image forming device that forms the identification code 100, the same image forming device as the image forming device that executes the first image forming operation may be used.

  As described above, the color forming the identification code 100 is determined by the image forming apparatus 20 that performs the first image forming operation.

<Operation of Characteristic Part of Image Forming Apparatus (First Image Forming Operation)>
In the image forming apparatus 1, when the execution mode of the first image forming operation is selected and instructed from the input unit 14 a of the operation display device 14 by the service engineer, the following first image forming operation is executed by the control unit 61. The

  The first image forming operation at this time is, for example, in each image forming device 20 (Y, M, C, K) while operating four image forming devices 20 (Y, M, C, K) one by one. It is executed multiple times. Here, representatively, the first image forming operation when the black color K image forming device 20K is operated will be described.

  When it is time to execute the first image forming operation, the image forming device 20K is charged by the charging device 22 so that the image formable range 210 of the rotating photosensitive drum 21 becomes the same charging potential: Vh1 as that during normal image formation. Then, the light passes through the exposure device 23 without being exposed to light and passes through the development device 24K to which the development bias for the first image forming operation is supplied, and development is performed.

  At this time, as shown in FIG. 5B, the photosensitive drum 21 in the image forming device 20K is charged so that the image formable range 210 becomes a negative polarity charging potential: Vh1, while the first drum The developing bias for the image forming operation is supplied and the developing roller 241 of the developing device 24K having a special developing potential: Vd2 having a negative polarity exceeding the charging potential: Vh1 is opposed to the developing roll 241.

  As a result, a potential difference: Δα1 (= Vd2−Vh1) is generated between the photosensitive drum 21 and the developing roll 241 to develop the end portions 215 and 216 outside the image quality guarantee range of the photosensitive drum 21. For example, when “−550 V” is applied as the charging potential: Vh1 and “−600” is applied as the special development potential: Vd2, the potential difference: Δα1 is an absolute value of “50V”.

  As a result, the photosensitive drum 21 is developed with black toner charged to the negative polarity in the entire image formable range 210 including the end portions 215 and 216 outside the image quality guarantee range.

  Subsequently, the black toner image formed on the photoconductive drum 21 during the first image forming operation is primarily transferred to the intermediate transfer belt 31 of the intermediate transfer device 30 and conveyed, and then subjected to special recording at the secondary transfer position. Secondary transfer is performed on the sheet 9B. Finally, the black toner image at the time of the first image forming operation is fixed on the special recording paper 9B by the fixing device 50, and then output to the discharge container 12 in a state of being recorded on the special recording paper 9B. .

  Thus, the first image forming operation by the operation of the image forming device 20K is completed. This first image forming operation is executed a plurality of times by changing at least one of the charging potential: Vh1 and the special development potential: Vd2 of the photosensitive drum 21.

  As a special development potential, as long as a potential difference that can develop the end portions 215 and 216 that are outside the image quality guarantee range of the photosensitive drum 21 can be obtained, a two-dot chain line in FIG. 5B is exemplified. In addition, it is also possible to apply a developing potential: Vd3 that is a potential before the charging potential: Vh1 during normal image formation. The potential difference at this time is Δα2.

  If such a special development potential: Vd3 is adopted when the level of dark decay of the wear portion 219 on the photosensitive drum 21 is relatively large, the wear portion 219 is developed even with the development potential Vd3 (potential difference Δα2). This is particularly effective.

  In the first embodiment, the end portions 215 and 216 that are out of the image quality guarantee range of the photosensitive drum 21 are also developed in the first image forming operation, so that the development current supplied from the power feeding unit 15 can be developed. A corresponding configuration example is shown by changing to generate Δα1 (Δα2). However, in the first image forming operation, for example, the potential difference Δα1 (Δα2) generates the charging bias supplied from the power supply unit 15 while maintaining the developing current at the value of the developing bias when forming a normal image. You may change and respond | correspond. In addition, in the first image forming operation, both the developing bias and the charging bias may be changed (adjusted) so as to generate the potential difference Δα1 (Δα2).

  Further, in the first embodiment, prior to the first image forming operation by the image forming device 20K, at least one image forming device 20 (Y, M, Y) of yellow (Y), magenta (M), and cyan (C) is used. C) is used to form an identification code 100 as an example of identification information for identifying information related to the result of the first image forming operation on the special recording sheet 9B.

  Further, in the first image forming operation, after the operation process by the operation of the black image forming device 20K is completed, the remaining color image forming devices 20 (Y, M, C) are sequentially operated independently. It is executed in the same way.

  When this first image forming operation is executed, the service engineer examines and examines the image on the special recording sheet 9B that is finally output. Thereby, the service engineer can know whether or not there is a sign of abnormality such as at least the end of the image quality guarantee range in the photosensitive drum 21 being worn (end wear).

  That is, on the output special recording paper 9B, as shown in FIGS. 6 and 9, an image in which the toner is almost uniformly attached to the entire area of one side is formed.

  At this time, for example, in the vicinity of the left and right end portions in the width direction W substantially perpendicular to the transport direction E of the special recording paper 9B after output, for example, it extends in a streak pattern along the transport direction E illustrated in FIG. When it is confirmed that the visible dark image portions K1 and K2 exist, it is possible to know that there is a sign that an abnormality such as end wear of the photosensitive drum 21 occurs.

  On the other hand, when the presence of the dark image portions K1 and K2 that look like stripes in the vicinity of the left and right edges of the special recording paper 9B after output is not confirmed, it is referred to as end wear of the photosensitive drum 21. You can know that there is no sign that an abnormality will occur.

  Further, when the service engineer confirms the presence of dark image portions K1 and K2 that appear to be streaks at the left and right edges of the special recording paper 9B by the first image forming operation, the service engineer checks the edges of the photosensitive drum 21. Arrangement is made to replace the photosensitive drum 21 with the presence of the image portions K1 and K2 with a new photosensitive drum, or it is determined that this is a sign of abnormal wear, or a new photosensitive member. If you have a drum, you can replace it on the spot.

  When such measures are taken, it is possible to prevent the occurrence of image defects due to end wear on the photosensitive drum 21. Further, by preventing the occurrence of an image defect due to the end wear, the unusable time (ie, the image forming apparatus 1 cannot be used during the operation of specifying and repairing the cause of the image defect) ( The occurrence of downtime can also be prevented.

In the first embodiment, as shown in FIG. 9, identification codes 100 respectively corresponding to a plurality of special recording sheets 9B ₁ , 9B ₂ ,... 9B _n output by the first image forming operation. Added. For this reason, the service engineer visually reads the identification code 100 made up of character information such as “sample 1” or the like, or reads the identification code 100 made up of a two-dimensional barcode with a barcode reader, so The recording sheets 9B ₁ , 9B ₂ ,... 9B _n can be distinguished from each other. As the bar code reader, a smartphone equipped with a bar code reading function possessed by a service engineer may be used.

The information identified by the identification code 100 includes the identification information of the photosensitive drum 21, the charging potential of the photosensitive drum 21: the value of Vh1, the developing potential of the developing device 24: the value of Vd2, and the first image forming operation. It is possible to know the environmental conditions such as the temperature and humidity in the image forming apparatus 1 at the time, and the plurality of output special recording sheets 9B ₁ , 9B ₂ ,... 9B _n are mutually identified and managed. It becomes possible.

[Embodiment 2]
FIG. 13 shows the configuration and state of the second image forming operation in the image forming apparatus according to the second embodiment. The image forming apparatus according to the second embodiment is related to the first embodiment except that a configuration capable of executing the second image forming operation by the control unit 61 is added as a function of knowing a sign of abnormality related to at least some parts. The image forming apparatus 1 has the same configuration.

<Function to know signs of component abnormality>
In addition to the configuration related to the first image forming operation, the image forming apparatus 1 according to the second embodiment has a function for knowing a sign of abnormality such as at least wear of the end of the image quality guarantee range 212 in the photosensitive drum 21. The following configuration is provided. Further, the image forming apparatus 1 has a function of making it possible to identify a plurality of pieces of information for knowing a sign of abnormality such as wear of at least the end of the image quality guarantee range 212 on the photosensitive drum 21.

  That is, in this image forming apparatus, as shown in FIG. 3 and FIG. 13, the control means 61 in Embodiment 1 charges the image forming range 210 of the photosensitive drum 21 with the charging device 22 and uses the developer. The second image forming operation including the developing operation and the developing operation with the developer without charging the image forming range 210 of the photosensitive drum 21 by the charging device 22 can be executed. Further, in this image forming apparatus, the output unit 70 in Embodiment 1 is configured to output information on the result of the second image forming operation, as shown in FIG. The former operation in the second image forming operation (operation in which the image forming range 210 of the photosensitive drum 21 is charged by the charging device 22 and developed with the developer) is an operation corresponding to the first image forming operation. Can be treated as being.

  When performing the second image forming operation (the former and the latter operations), the control unit 61 switches whether or not to supply the charging bias from the power supply unit 15 (supply or non-supply) and also supplies the power supply unit. The developing bias supplied from 15 is changed so that a potential difference (Δα) that can be developed by the developer in the image formable range 210 of the photosensitive drum 21 can be generated. Further, when executing the second image forming operation, the control unit 61 controls the operation of the exposure driving unit 16 so that the exposure by the exposure device 23 is not performed and the electrostatic latent image is not formed.

  First, when executing the former operation (actually the first image forming operation) of the second image forming operation, the control unit 61 is similar to the case of the first image forming operation in the first embodiment in the same way as the power supply unit 15. As shown in FIG. 13A, the end portions 215 and 216 outside the image quality guarantee range of the photosensitive drum 21 can be developed with the developer supplied from the developing device 24. The condition is changed to a condition for generating the potential difference Δα.

  As illustrated in FIG. 13A, the developing bias at this time is a special developing potential Vd2 generated when a changed developing bias is supplied, and a charging potential when a normal image is formed: A current that has a potential exceeding the absolute value of Vh1 is employed. Further, the potential difference Δα at this time becomes a potential difference Δα1 which is a difference (absolute value) between the charging potential: Vh1 and the special development potential: Vd2.

  Next, when performing the latter operation of the second image forming operation, the control unit 61 stops (not supplies) the supply of the charging bias from the power supply unit 15 as illustrated in FIG. Thus, the image forming range 210 of the photosensitive drum 21 is not charged (charging potential: Vh2 = 0), while the developing bias has a potential difference ΔΔ3 that allows development in the image forming range 210 of the photosensitive drum 21. Change the current to As the special development potential Vd4 at this time, a value is used in which the potential difference Δα3 is substantially the same as the potential difference Δα1 in the first image forming operation.

  Further, the second image forming operation by the control means 61 is instructed by the service engineer selecting the execution mode of the second image forming operation from the input unit 14a of the operation display device 14 as in the case of the first image forming operation. When configured to run.

  In this case, the execution mode of the second image forming operation is displayed as a selection instruction screen on the display unit 14b of the operation display device 14, for example. In the second embodiment, the selection instruction screen regarding the execution mode of the second image forming operation is, for example, a case where the execution mode of the first image forming operation is selected and instructed, and the first image forming operation is performed. Is configured to be displayed for the first time after ending. Further, the control means 61 is configured to control to execute the second image forming operation after executing the first image forming operation. Incidentally, the second image forming operation is not performed unless an operation for selecting and instructing the execution mode of the second image forming operation after performing the first image forming operation is performed.

  For example, as in the case of the output unit 70 for the first image forming operation in the first embodiment, the output unit 70 is a developer image (unfixed toner image) formed on the photosensitive drum 21 by the second image forming operation. ) On the recording paper 9 and output. However, the recording paper 9 used for this output has the same feed width as the axial dimension of the image formable range 210 of the photosensitive drum 21 as in the case of outputting the result of the first image forming operation. A special recording sheet 9B that is handled as an exception is used (FIG. 14).

<Second image forming operation>
In the image forming apparatus 1, when the service engineer selects and instructs the execution mode of the first image forming operation and the second image forming operation from the input unit 14 a of the operation display device 14, the control unit 61 performs the following first operation. An image forming operation and a second image forming operation are executed. Note that the first image forming operation at this time is the former operation in the second image forming operation as described above.

  Also, the second image forming operation is performed a total of four times while operating the four image forming devices 20 (Y, M, C, K) one by one, as in the case of the first image forming operation. Here, as a representative example, the first image forming operation when the black color K image forming device 20K is operated will be described.

  First, when the first image forming operation which is also the former operation in the second image forming operation is performed, the image forming apparatus 20K rotates as in the case of the first image forming operation according to the first embodiment described above. The image forming range 210 of the photosensitive drum 21 to be charged is charged by the charging device 22 so as to have the same charging potential: Vh1 as in normal image formation, and then passes without being exposed to the exposure device 23, and the first work Development is performed through the developing device 24K to which a developing current for image operation is supplied.

  At this time, the photosensitive drum 21 in the image forming device 20K is charged so that the image formable range 210 has a negative polarity charging potential: Vh1, while the developing current for the first image forming operation is supplied. This is opposed to the developing roll 241 of the developing device 24K having a special developing potential: Vd2 having a negative polarity exceeding the charging potential: Vh1.

  As a result, as shown in FIG. 13A, the photosensitive drum 21 has a photosensitive potential 21 between the charge potential Vh1 of the image formable range 210 and the special developing potential Vd2 generated on the developing roll 241 as shown in FIG. A potential difference ΔΔ1 for developing the end portions 215 and 216 outside the image quality guarantee range of the body drum 21 is generated. As a result, the entire photosensitive drum 21 including the end portions 215 and 216 outside the image quality guarantee range is developed with black toner charged with a negative polarity.

  Subsequently, the black toner image formed on the photoconductive drum 21 during the first image forming operation is primarily transferred to the intermediate transfer belt 31 of the intermediate transfer device 30 and conveyed, and then subjected to special recording at the secondary transfer position. Secondary transfer is performed on the sheet 9B. Finally, the black toner image at the time of the first image forming operation is fixed on the special recording paper 9B by the fixing device 50, and then output to the discharge container 12 in a state of being recorded on the special recording paper 9B. .

  Thus, the first image forming operation by the operation of the image forming device 20K is completed. The first image forming operation is similarly performed by sequentially operating the image forming apparatuses 20 (Y, M, C) of colors other than the black color independently.

  By executing the first image forming operation (the former operation in the second image forming operation), special recording paper 9B for four colors (Y, M, C) on which the result of the image forming operation is recorded is obtained. (FIG. 14).

  At this time, as in the case of the first image forming operation in the first embodiment, the service engineer looks at the output image on the special recording sheet 9B and examines it, so that at least the end of the photosensitive drum 21 is obtained. It is possible to know whether or not there is a sign of abnormality such as partial wear. That is, the density appears to extend in a streak pattern along the conveyance direction E illustrated in FIG. 14 near the left and right ends of the width direction W substantially perpendicular to the conveyance direction E of the special recording paper 9B after output. When the dark image portions K1 and K2 exist, it can be known that there is a sign that an abnormality such as end wear of the photosensitive drum 21 occurs.

  However, in the portion corresponding to the image quality guarantee range of the special recording paper 9B output by the execution of the first image forming operation, as shown in FIG. 14, the image portion K1, K2 has a different darkness. There may be a case where the image portion K3 exists.

  In this case, it is difficult to determine that there is a sign of another abnormality other than end wear in the photosensitive drum 21 based only on the presence of the image portion K3. In particular, when the image portion K3 periodically exists at substantially the same interval along the conveyance direction E of the special recording paper 9B, the image portion K3 exists in a portion different from the image portions K1 and K2. Therefore, it cannot be determined that it is a sign that at least an abnormality such as end wear of the photosensitive drum 21 occurs. The second image forming operation (the latter operation) is effective when executed in such a case.

  Next, when the latter operation in the second image forming operation is executed, in the image forming device 20K, the image forming range 210 of the rotating photosensitive drum 21 is not charged by the charging device 22, and the next exposure device 23 is not charged. Then, the image is passed through the developing device 24K to which the developing current for the second image forming operation is supplied.

  At this time, as shown in FIG. 13B, the photosensitive drum 21 of the image forming device 20K is not charged in the image formable range 210 and is in a charged potential: Vh2 = 0. 2. A developing current for image forming operation is supplied to face the developing roll 241 of the developing device 24K having a special developing potential: Vd3 having a negative polarity larger than the charging potential: Vh2 = 0.

  As a result, between the charged potential: Vh2 = 0 in the image formable range 210 of the photosensitive drum 21 and the special developing potential: Vd4 generated on the developing roll 241 is outside the image quality guarantee range of the photosensitive drum 21. A potential difference ΔΔ3 that can develop the end portions 215 and 216 is generated. For example, when “−50” is applied as the special development potential: Vd4 with respect to the charging potential: Vh2 = 0, the potential difference Δα3 is “50V” in absolute value. This potential difference Δα3 is the same as the potential difference Δα1 applied during the first image forming operation. As a result, the photosensitive drum 21 is developed with black toner charged to the negative polarity in the entire image formable range 210 including the end portions 215 and 216 outside the image quality guarantee range.

  Subsequently, the black toner image formed on the photoconductive drum 21 during the second image forming operation is primarily transferred to the intermediate transfer belt 31 of the intermediate transfer device 30 and conveyed, and then subjected to special recording at the secondary transfer position. Secondary transfer is performed on the sheet 9B. Finally, the black toner image at the time of the second image forming operation is fixed on the special recording paper 9B by the fixing device 50, and then is output to the discharge container 12 in a state of being recorded on the special recording paper 9B. .

  Thus, the latter operation in the second image forming operation by the operation of the image forming device 20K is completed. The operations described later in the second image forming operation are similarly executed by sequentially operating the image forming apparatuses 20 (Y, M, C) of colors other than black independently.

  Even when the latter operation in the second image forming operation is executed, a special recording sheet 9B is finally output and can be obtained. At this time, the service engineer can also know whether there is another sign of abnormality in addition to the sign of abnormal end wear on the photosensitive drum 21 by examining the image on the special recording paper 9B. it can.

  That is, at this time, as illustrated in FIG. 15, when the dark image portion K3 that exists at the end of the first image forming operation does not exist on the special recording paper 9B, the image portion K3 is displayed. The charging device 22 can be regarded as having disappeared due to the absence of charging, and it can be known that there is a sign of abnormality such as damage or functional deterioration that causes the image portion K3 to be formed on a part of the charging roll 221.

  This is within the image formable range 210 of the photosensitive drum 21 charged with the damaged or function-degraded portion when there is a damaged or function-degraded portion that causes a charging failure in a part of the charging roll 221. The charging potential of the portion: Vh is lower than that of the other portions, and the potential difference from the development potential: Vd is also relatively large. As a result, the portion where the charged potential of the photosensitive drum 21 is lowered is easily developed and a lot of toner adheres, and the image portion K3 corresponding to the portion is formed and visualized. doing.

  At this time, if the period (interval) of the image portion K3 is a dimension corresponding to the outer peripheral length (circumference) of the charging roll 221, the image portion K3 may damage the above-described damage or damage to a part of the charging roll 221. There is a further possibility that the information indicates a sign of abnormality such as functional deterioration. Therefore, when such a result is obtained, the service engineer can cope with prompt replacement of the corresponding charging device 22 (charging roll 221) with a new one.

  On the other hand, if the special recording paper 9B output at this time (FIG. 15) similarly has the dark image portion K3 (FIG. 14) that existed at the end of the first image forming operation, It can be inferred that damaged or functionally deteriorated portions are generated at substantially the same interval in the circumferential direction within the image quality guarantee range of the photosensitive drum 21. In this case, a normal charged potential cannot be obtained at a portion where the photosensitive drum 21 is damaged or the function is deteriorated, and there is a high possibility that an image defect due to the charged potential will occur. Therefore, when such a result is obtained, the service engineer can cope with prompt replacement of the corresponding photosensitive drum 21 with a new one.

  Even when the latter operation in the second image forming operation is performed, the output special recording paper 9B has a sign of an abnormality such as end wear on the photosensitive drum 21, as shown in FIG. The image portions K1 and K2 indicating the same appear as in the case of the output result of the first image forming operation (FIG. 14). In addition, the image portion K3 may appear in a portion of the special recording paper 9B corresponding to the end portions 215 and 216 outside the image quality guarantee range of the photosensitive drum 21.

  Further, as illustrated in FIG. 14, the special recording paper 9B output when the first image forming operation is performed, as illustrated in FIG. 14, has another image portion K4 that is wider in the transport direction E than the image portion K3. May appear.

  In this case, if the interval between the image portions K4 is a dimension that may not be generated from the circumference of the charging roll 221, the image portion K4 is substantially in the circumferential direction within the image quality guarantee range of the photosensitive drum 21. It can also be inferred that this is a result obtained by damage occurring at the same interval or a part with degraded function.

  However, even in this case, as illustrated in FIG. 15, the special recording sheet 9 </ b> B output when the latter operation in the second image forming operation is executed following the first image forming operation, If it can be confirmed that the image portion K4 still appears, it can be confirmed with certainty that there is a sign of abnormality such as damage or functional deterioration in a part of the image quality guarantee range of the photosensitive drum 21.

[Embodiment 3]
FIG. 16 is a schematic configuration diagram showing an image forming apparatus according to Embodiment 3 of the present invention.

  The same parts as those in the first embodiment will be described with the same reference numerals. As shown in FIG. 16, the image forming apparatus 1 has one housing inside the housing 10 unlike the first embodiment. This is a monochrome image forming apparatus including only the image forming apparatus 20.

  In the image forming apparatus 1, during normal image formation, as shown in FIG. 17A, the peripheral surface of the photosensitive drum 21 is charged to the required potential Vh by the charging device 22 and the developing device 24 develops the image. A required developing bias potential Vd is applied to the roll 241. An exposed portion of the potential Vi formed by image exposure on the peripheral surface of the photosensitive drum 21 is a toner that is reversely developed in accordance with a developing potential that is a potential difference (Vd−Vi) from the developing bias potential Vd of the developing roll 241. It is visualized by.

  Further, as shown in FIG. 17B, the control unit 61 sets the charging potential of the photosensitive drum 21 without applying a charging bias to the charging roll 221 of the charging device 22, for example, during the second image forming operation. Control is performed so that the developing bias Vd5 of about −50V is supplied to the developing roll 241 of the developing device 24. The peripheral surface of the photosensitive drum 21 moves to a developing area facing the developing roll 241 of the developing device 24 as the photosensitive drum 21 rotates. At this time, the potential of the photosensitive drum 21 is 0 V, but when supplied to the developing roll 241 of the developing device 24, the developing bias is about −50 V, which is relatively to the potential of the photosensitive drum 21. Low potential. For this reason, the negatively charged toner held on the surface of the developing roll 241 moves to the photosensitive drum 21 side according to the potential difference between the photosensitive drum 21 and the developing roll 241 of the developing device 24, and the photosensitive drum 21. The toner adheres substantially uniformly to the peripheral surface of the toner and is bias-developed. As shown in FIG. 18A, the toner image developed on the peripheral surface of the photosensitive drum 21 is transferred to a special recording sheet 9B by the transfer device 25 and fixed by the fixing device 50, and then discharged and accommodated. Part 12 is accommodated.

  Further, the control unit 61 changes the value of the developing bias supplied to the developing roll 241 of the developing device 24 a plurality of times, and outputs a plurality of special recording sheets 9B.

  In the image forming apparatus 1 according to the third embodiment, as shown in FIG. 17C, when the second image forming operation is executed, the control unit 61 develops the rear end portion of the special recording paper 9B. The developing bias Vd5 supplied to the roll 241 is turned ON / OFF according to the identification information or changed to a different value Vd6, and an identification code 100 having a density different from that of the image of the second imaging operation is formed at the rear end of the special recording paper 9B. It is comprised so that may be added.

  As a result, as shown in FIG. 18B, an identification code 100 composed of a one-dimensional barcode indicating the execution condition of the second image forming operation is formed at the rear end of the special recording paper 9B. . Here, the identification code 100 is not limited to a one-dimensional barcode according to the standard. As long as the gray levels of the images are arranged in a one-dimensional manner and can be distinguished from each other, the interval and width of the gray image are not limited. Of course, it can be set freely.

  The identification code 100 made up of a one-dimensional barcode is composed of a plurality of one-dimensional linear images having different intervals and line widths along the conveyance direction of the recording paper 9. One-dimensional barcode information is expressed by the interval and line width of a linear image. For example, a blank area where a linear image is not formed or a uniform density area having a required width is provided at both ends along the arrangement direction of the one-dimensional barcode. Then, identification information is recorded between a pair of blank areas or uniform density areas having a required width located at both ends along the arrangement direction of the one-dimensional barcode. The interval between adjacent linear images is set to be 7 times or more the width of the linear image having the narrowest barcode. The width of the other linear image in the barcode is set to a required value such as a ratio of 2: 1, 3: 1, or 5: 1 that is predetermined for the width of the thinnest linear image. In the identification code 100 composed of a one-dimensional barcode, for example, a number of about 8 to 13 digits can be expressed.

  The control means 61 controls the development bias value and the application timing corresponding to the interval and line width of the linear images according to the identification information desired to be expressed.

  Since the third embodiment includes only one imaging device 20, it is necessary to form the identification code 100 with a single imaging device 20. However, since the image can be formed on both sides of the recording paper 9 as in the first embodiment described above, the image by the second image forming operation is formed on one side of the recording paper 9, and the recording paper It is also possible to form character information including a two-dimensional barcode on the other surface of 9 by a normal image forming operation. Similarly to the above-described first embodiment, an image formed by the first image forming operation is formed only on a partial area on one side of the recording paper 9, and two-dimensionally formed on the other area of the recording paper 9 by a normal image forming operation. It is also possible to form character information including a barcode.

  In the first embodiment, the case where the service engineer operates the input unit 14a of the operation display device 14 to execute the first image forming operation in the special mode has been described. However, in the third embodiment, the control unit 61 may be configured to automatically execute the first image forming operation according to the total number of prints of the recording paper 9.

  At this time, in the first image forming operation, it is necessary to use a special recording sheet 9 different from the recording sheet 9 that is normally used by the user. However, the control unit 61 displays the first image forming operation on the display unit of the operation display device 14. And by prompting the user to store the special recording paper 9 in the storage unit.

  In the third embodiment, the case where the identification code 100 is formed by switching the developing bias of the developing device 24 without charging the peripheral surface of the photosensitive drum 21 has been described, but as described in the first embodiment. In the case of bias development for controlling the developing bias Vb with respect to the charged potential Vh of the photosensitive drum 21, an image with the identification code 100 may be formed by exposure by the exposure device 23. In this case, the exposure potential by the exposure device 23 is set to the normal image formation so that the developing potential becomes too high as in normal image formation and the image density accompanying the first image forming operation becomes excessive. It is desirable to lower the time or control the developing bias Vb.

  In the third embodiment, the case where the identification code 100 is formed by switching the developing bias of the developing device 24 has been described. However, the primary transfer bias of the transfer device 25 or the secondary transfer device 35 in the first embodiment is described. As shown in FIG. 17C, the transfer bias may be controlled by the control unit 61 so that the identification code 100 is formed.

[Other embodiments]
In the first and second embodiments, as the output unit 70, for example, an output unit 70 having another configuration described below may be applied. The output means 70 includes a reading means 72 for reading the toner image transferred to the intermediate transfer belt 31 when the first image forming operation or the second image forming operation is executed, and information on the image read by the reading means 72. And an output unit 75 for outputting.

  As the reading unit 72, for example, a line type density sensor that has a reading surface over the entire width direction of the intermediate transfer belt 31 and can individually read four color toner images is applied. As illustrated in FIG. 1, the reading unit 72 passes through all of the image forming devices 20 (Y, M, C, K) of the intermediate transfer belt 31 and reaches the secondary transfer position (image holding surface ( The outer peripheral surface) is disposed at a position facing the portion, preferably at a position facing the image holding surface portion supported by the support roll 32b or the like.

  The output unit 75 outputs the read information to a device capable of confirming the information after storing the information once or immediately. As such an output unit 75, for example, a unit that displays information read and output to the display unit 14b of the operation display device 14 can be applied. In this case, for example, the position and density of the toner image secondarily transferred to the intermediate transfer belt 31 are displayed on the display unit 14b.

  When the output unit 70 configured by the reading unit 72 and the output unit 75 is adopted, the service engineer displays the result of the first image forming operation and the second image forming operation on the operation display device 14. It can be easily confirmed by looking at the content displayed on the part 14b. Also in this case, whether there is at least a sign of abnormality such as end wear in the photosensitive drum 21 by checking the presence or absence of the image portions K1 and K2 and the presence or absence of other image portions K3 and K4 in the display image. You can know whether or not.

  Incidentally, when outputting the read information, the toner image transferred onto the intermediate transfer belt 31 may be removed by the belt cleaning device 36 without being secondarily transferred to the recording paper 9 or the like. Further, when the results of the first image forming operation and the second image forming operation are displayed and output on the display unit 14b as described above, it is not necessary to use the special recording paper 9B described above. Further, the output means 70 may be configured to have a function of recording and outputting the results of the first image forming operation and the second image forming operation on the special recording paper 9B described above. The output unit 75 may be configured to output (including transmission) the read information to an external device other than the image forming apparatus 1.

  In the first and second embodiments, the control unit 61 increases or decreases the potential difference Δα with respect to the developing current and the charging current supplied from the power supply unit 15 when the first image forming operation and the second image forming operation are executed. It is also possible to adopt a configuration in which control is performed so that the supply is changed as described above. When this configuration is adopted, an image portion (K1, K2, etc.) showing a sign of abnormality is identified by adjusting the density difference of the images obtained by executing the first image forming operation and the second image forming operation. It can be made easier.

  In the second embodiment, when the former operation in the second image forming operation is executed, the charged photosensitive drum 21 is applied to the charged photosensitive drum 21 by the exposure device 23 as illustrated by a two-dot chain line in FIG. An electrostatic latent image may be formed within the image quality guarantee range by performing exposure. In this case, for example, a latent image of a halftone (intermediate density) image using a screen can be applied as the electrostatic latent image. When forming an electrostatic latent image in this way, the former operation in the second image forming operation has a configuration different from that of the first image forming operation (when no electrostatic latent image is formed).

  Further, the image forming apparatus is not limited to the image forming apparatus 1 that employs the intermediate transfer system exemplified in the first and second embodiments as long as the image forming apparatus includes a photoconductor, a contact-type charging device, and a developing device. Alternatively, other types of image forming apparatuses may be used.

  When an image forming apparatus that does not employ the intermediate transfer method is applied, the reading unit 72 in the output unit 70 reads the toner image formed on the photoconductor when the first image forming operation or the second image forming operation is performed. Become.

  In the above-described embodiment, the contact-type charging device has been mainly described as the charging device. However, uneven wear of the photoconductor also occurs due to a cleaning blade or the like that cleans the surface of the photoconductor. Of course, it is not limited to the charging device.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 9 ... Recording paper (an example of a recording medium)
9B: Special recording paper (an example of a recording medium)
14b ... Display section (an example of display means)
21. Photosensitive drum (an example of a photosensitive member)
31. Intermediate transfer belt (an example of an intermediate transfer member)
22 ... Charging device 24 ... developing device 61 ... control means 70 ... output means 72 ... reading means 75 ... output section 210 ... image formable range 215, 216 ... end outside image quality guarantee range Δα ... potential difference

Claims (5)

Image holding means having an image quality guarantee range within an image formable range;
Charging means for charging at least an image forming range of the image holding means;
Developing means for developing the electrostatic latent image formed on the image holding means with a developer;
Control means for executing a first image forming operation for developing at least an end portion outside the image quality guarantee range of the image holding means of the image holding means with a developer;
Output means for outputting information on the result of the first image forming operation;
Adding means for adding identification information for identifying information related to the result of the first image forming operation;
An image forming apparatus comprising: The control unit is configured to charge the image forming range of the image holding unit with the charging unit and develop with the developer, and with the developer without charging the image forming range of the image holding unit with the charging unit. Configured to perform a second image forming operation including an operation of developing,
The image forming apparatus according to claim 1, wherein the adding unit adds the identification information by the second image forming operation. A developing voltage feeding means capable of supplying a developing voltage to the developing means;
The image forming apparatus according to claim 1, wherein the adding unit adds the identification information by switching between supply and non-supply of a development voltage supplied from the development voltage power supply unit or a value of the development voltage. Transfer means for transferring the image held by the image holding means to an intermediate transfer member or a recording medium;
A transfer voltage feeding means capable of supplying a transfer voltage to the transfer means;
The image forming apparatus according to claim 1, wherein the adding unit adds the identification information by switching between supply and non-supply of a transfer voltage supplied from the transfer voltage power supply unit or a value of the transfer voltage. A plurality of image forming means having the image holding means, the charging means and the developing means;
With
The image forming apparatus according to claim 1, wherein the adding unit adds identification information using the image forming unit that does not execute the first image forming operation.

Images