JP7069782B2 - Image forming device - Google Patents

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 an abnormal image, for example, those described in the following Patent Documents 1 to 5 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 or not an abnormal image is generated. An image forming apparatus is shown in which a sign that an abnormal image is generated before an abnormality occurs is found, and treatment is taken at an early stage. Further, Patent Document 1 exemplifies that the fixing roller and the pressure roller of the fixing device are deformed and that the photosensitive drum has a large amount of water as the abnormality.

Further, Patent Document 2 describes a state determining means for calculating a deviation amount of image data with respect to a normal state and determining whether or not it is an abnormal state based on the deviation amount, and an abnormality for identifying an abnormal portion from the state of an image forming apparatus. When the location specifying means and the state determining means determine that the abnormality is present, the image processing means that performs image processing for the abnormality according to the output of the abnormal location identifying means, and the state determining means determine that the abnormality is present. Shows an image forming apparatus including a serviceman call output means for outputting a serviceman call signal.

Further, Patent Document 3 describes an image input means, an image forming means for forming an output image on a recording medium based on the input image data, an discharging means for discharging the recording medium on which the image is recorded, and a discharging means. An image reading means for outputting the scanned image obtained by reading the recorded recording medium, an abnormality detecting image generating means for outputting abnormality detecting image data in which an abnormal image is likely to be generated due to the charging unit of the image forming means, and an abnormality thereof. It has a comparison means that compares the output data from the image reading means that reads the recording medium on which the output image is formed based on the detection image data and the input abnormality detection image data, and outputs the determination result. An image forming apparatus having a determination means capable of detecting the presence or absence of an abnormality in a charging unit based on the determination result of the comparison means is shown.

Further, in Patent Document 4, a plurality of latent image carriers are provided, and a step of transferring an image from each latent image carrier to a transfer body, and a failure of an optical sensor and an image forming apparatus directed to the transfer body occur. In an image forming apparatus equipped with a failure detecting means for making a prediction, when the occurrence of color streaks is predicted, a transfer bias is applied to the transfer body for each latent image carrier, and the transfer body is subjected to the failure detection means. An image forming apparatus having a mode for detecting the surface state of is shown. Further, Patent Document 4 also shows that the image forming apparatus can identify an image forming portion of a color in which a sign of image defect such as a color streak is generated by this image forming apparatus.

Further, Patent Document 5 describes an image processing apparatus having an image forming means for forming an image, and an acquisition means for acquiring a feature amount from a result of reading a chart formed by the image forming means, and an acquisition means for acquiring the feature amount. It has a determination means for determining whether or not the image formed by the image forming means contains defects according to the determined feature amount, and a notification means for notifying information about the result determined by the determination means, and the acquisition thereof. An image processing apparatus having a determination means for determining whether or not to add an image generated from a result of reading a chart to information to be notified by the notification means is shown according to the feature amount acquired by the means.

Japanese Unexamined Patent Publication No. 2004-133081 Japanese Unexamined Patent Publication No. 2007-334269 Japanese Unexamined Patent Publication No. 2008-170549 Japanese Unexamined Patent Publication No. 2008-292973 Japanese Unexamined Patent Publication No. 2016-46595

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

The invention according to claim 1 comprises an image holding means having an image quality guarantee range within a range in which an image can be formed, and an image holding means.
A charging means for charging at least an image forming range of the image holding means, and a charging means.
A developing means for developing an electrostatic latent image formed in the image holding means with a developing agent,
A control means for executing the first image forming operation of developing at least an end portion of the image forming range of the image holding means that is out of the image quality guarantee range with a developer.
An output means for outputting information regarding the result of the first image formation operation, and
An additional means for adding identification information that identifies information regarding the result of the first image formation operation to the image imaged by the first image formation operation , and
A developing voltage feeding means capable of supplying a developing voltage to the developing means, and a developing voltage feeding means.
Equipped with
The addition means is an image forming apparatus that adds the identification information by switching the supply and non-supply of the development voltage supplied from the development voltage feeding means or the value of the development voltage .

The invention according to claim 2 comprises an image holding means having an image quality guarantee range within a range in which an image can be formed, and an image holding means.
A charging means for charging at least an image forming range of the image holding means, and a charging means.
A developing means for developing an electrostatic latent image formed in the image holding means with a developing agent,
A control means for executing the first image forming operation of developing at least an end portion of the image forming range of the image holding means that is out of the image quality guarantee range with a developer.
An output means for outputting information regarding the result of the first image formation operation, and
An additional means for adding identification information that identifies information regarding the result of the first image formation operation to the image imaged by the first image formation operation , and
A transfer means for transferring an image held by the image holding means to an intermediate transfer body or a recording medium, and a transfer means.
A transfer voltage feeding means capable of supplying a transfer voltage to the transfer means,
Equipped with
The addition means is an image forming apparatus that adds the identification information by switching the supply and non-supply of the transfer voltage supplied from the transfer voltage feeding means or the value of the transfer voltage.

The invention according to claim 3 comprises the image holding means, the charging means, and a plurality of image forming means having the developing means.
Equipped with
The additional means is the image forming apparatus according to claim 1 or 2 , wherein identification information is added by using the image forming means that does not execute the first image forming operation.

According to the first aspect of the present invention, it is possible to identify information that knows a sign that at least the end of the image quality guarantee range in the image holding means is worn.
Further, according to the first aspect of the present invention, the identification information is compared with the case where the identification information is added without switching the supply and non-supply of the development voltage supplied from the development voltage feeding means or the value of the development voltage. Can be easily added.

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

According to the third 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 by using the image forming unit that does not execute the first image forming operation. Identification information can be added by the normal image forming operation.

It is explanatory drawing which shows the structure of the image forming apparatus which concerns on Embodiment 1 and the like. It is explanatory drawing which enlarges and shows the structure of the image forming apparatus in the image forming apparatus of FIG. It is explanatory drawing which shows the structure of each part in a photosensitive drum. It is explanatory drawing which shows the process which edge wear occurs in a photosensitive drum, (a) shows the relationship between a photosensitive drum and a charge roll, (b) shows the initial state of uneven wear in a photosensitive drum, (c). Indicates a state in which uneven wear in the photosensitive drum is in progress, and (d) shows a state in which end wear occurs in the photosensitive drum. (A) is an explanatory diagram showing the potential relationship on the photosensitive drum when forming a normal image, and (b) is an explanatory diagram showing the potential relationship on the photosensitive drum when executing the first image forming operation. It is explanatory drawing which shows the result example which is output when the 1st image formation operation is executed. It is explanatory drawing which shows the structure of a part of the control system in the image forming apparatus of FIG. It is explanatory drawing which shows the image formed based on the conventional 1st image formation operation. It is explanatory drawing which shows the image formed based on the 1st image formation operation in Embodiment 1. FIG. It is explanatory drawing which shows a two-dimensional bar code. It is explanatory drawing which shows the image formed based on the 1st image formation operation in Embodiment 1. FIG. It is explanatory drawing which shows the image formed based on the 1st image formation operation in Embodiment 1. FIG. (A) is an explanatory diagram showing the potential relationship on the photosensitive drum when the second image forming operation (the operation of the first half) is executed in the image forming apparatus according to the second embodiment, and (b) is the second image forming operation (b). It is explanatory drawing which shows the potential relation on the photosensitive drum at the time of performing the operation of the latter half). It is explanatory drawing which shows the result example which is output when the 2nd image formation operation (the operation of the first half) is executed. It is explanatory drawing which shows the result example which is output when the 2nd image formation operation (the operation of the latter half) is executed. It is explanatory drawing which shows the structure of the image forming apparatus which concerns on Embodiment 3. It is explanatory drawing which shows the operation of the image forming apparatus which concerns on Embodiment 3. FIG. It is explanatory drawing which shows the image formed based on the 2nd image formation operation in Embodiment 3. FIG.

Hereinafter, embodiments 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 the 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. There is.

<Overall configuration of image forming apparatus>
The image forming apparatus 1 adopts an electrophotographic method and finally forms an image composed of toner on a recording sheet 9 which is an example of a recording medium based on image information consisting of characters, photographs, figures and the like. be. As shown in FIG. 1, the image forming apparatus 1 has a housing 10 having a box-shaped appearance as a whole. The image forming apparatus 1 has an image forming apparatus 20 as an example of an image forming means for forming a toner image composed of toner as a developer inside the housing 10, and a toner image formed by the image forming apparatus 20. The intermediate transfer device 30 that transfers the toner to the secondary transfer position for secondary transfer to the recording paper 9 after holding the toner by the primary transfer, and the recording paper 9 that is supplied to the secondary transfer position of the intermediate transfer device 30 are accommodated 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 arranged. The housing 10 is formed with a support structure portion and an exterior portion using, for example, materials such as a support member and an exterior material. The alternate long and short dash line shown in FIG. 1 is the main transport 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 and conditions related to the operation of the image forming apparatus 1 and a display unit 14b for displaying various information such as operation conditions and states. A central control device 60 and the like that collectively control the operation of the entire image forming apparatus 1 (such as the above-mentioned devices) are also arranged.

The image forming apparatus 1 according to the first embodiment has a function of knowing a sign of an abnormality related to at least a part of parts, as will be described later. Further, the image forming apparatus 1 also has a function of making it possible to distinguish a plurality of information for knowing a sign of abnormality of at least a part of the parts from each other.

The image forming apparatus 20 includes four image forming apparatus 20Y, 20M, which individually form four color developer (toner) images of yellow (Y), magenta (M), cyan (C), and black (K). It is configured using 20C and 20K. As shown in FIGS. 1 and 2, each of the image forming devices 20 (Y, M, C, K) is a photoconductor drum 21 as an example of an image holding means that is rotationally driven in the direction indicated by the arrow A. Each has. Around each photoconductor drum 21, a charging device 22 as an example of charging means, an exposure device 23 as an example of electrostatic latent image forming means, a developing device 24 as an example of developing means, and an example of primary transfer means. A primary transfer device 25, a drum cleaning device 26, a static eliminator 27, and the like are arranged.

The photoconductor drum 21 forms, for example, an image forming surface (image forming range) having a photodielectric layer (photoreceptor layer) made of a photosensitive material on the peripheral surface of a cylindrical or columnar conductive base material to be grounded. It is a photoconductor in the form of a drum. The photoconductor drum 21 is provided so as to receive power from a rotation drive device (not shown) and rotationally drive in the direction indicated by the arrow A.

The charging device 22 is, for example, a contact-type charging device provided with a charging roll 221 that is arranged in a state of being driven to rotate in contact with the image forming surface of the photoconductor drum 21 and to which a required charging bias having a negative polarity is supplied. Is. As shown in FIG. 2, the charging roll 221 is configured by covering the outer periphery of a rotating shaft 223 made of a cylindrical metal with a conductive elastic body layer 224. As shown in FIG. 3, the charging roll 221 is capable of driven rotation in a state where both ends of the rotating shaft 223 along the axial direction receive the required pressing force F and are pressed against the surface of the photoconductor drum 21. It is supported. The charging device 22 is not limited to the 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 by using a light emitting diode and optical components, or a scanning exposure apparatus configured by using optical components such as a semiconductor laser and a polygon mirror. be. In the exposure device 23, image information input from the outside through a communication means, a reading device, etc. and image information stored in an internal storage unit are subjected to necessary processing by an image processing device (not shown), and then each color component ( It is input as an image signal decomposed into Y, M, C, K). The exposure apparatus 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 containing a toner of one of the four colors (Y, M, C, K) and a magnetic carrier. Is. Further, the developing apparatus 24 (Y, M, C, K) is used, for example, to charge the toner to a negative polarity to perform reverse development. Further, as shown in FIG. 2, the developing apparatus 24 (Y, M, C, K) holds the two-component developer housed in the housing and conveys it to the developing region facing the photoconductor drum 21. A developing roll 241 or the like is provided as an example of a developer holder that rotates so as to perform. A development bias in which an AC component is superimposed on a DC component, for example, is supplied to the development roll 241 with the photoconductor drum 21.

The primary transfer device 25 is arranged so as to be in contact with the image forming surface portion to be the primary transfer position of the photoconductor drum 21 (via the intermediate transfer belt 31 described later) and to be driven to rotate, and is required to be primary. It is a contact type transfer device equipped with a primary transfer roll to which a transfer bias is supplied.

The drum cleaning device 26 is arranged so as to come into contact with at least the image-forming surface portion of the photoconductor drum 21 after the primary transfer at the opening for cleaning work of the housing, and removes unnecessary substances such as residual toner on the image-forming surface. It is equipped with a cleaning member such as an elastic plate that is scraped off and removed.

The static eliminator 27, for example, eliminates static electricity on the image-forming surface of the photoconductor drum 21 by exposure or the like to make the surface potential substantially zero.

The intermediate transfer device 30 is arranged at a position on the lower side of the four image drawing devices 20 (Y, M, C, K). The intermediate transfer device 30 is arranged so as to rotate in the direction indicated by the arrow B while passing through the primary transfer positions facing the primary transfer device 25 of the photoconductor drum 21 in the image drawing device 20 (Y, M, C, K). An intermediate transfer belt 31 is provided as an example of the intermediate transfer means to be performed.

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

Further, the intermediate transfer belt 31 is rotatably supported by being hung on a plurality of support rolls 32a to 32e. The support roll 32a is a drive roll, the support roll 32b is a driven roll that cooperates with the drive roll 32a to hold the primary transfer surface, 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.

Further, the intermediate transfer device 30 includes a secondary transfer device 35 as an example of a secondary transfer means for secondary transfer of a toner image transferred on the intermediate transfer belt 31 to a recording sheet 9, and an outer peripheral surface of the intermediate transfer belt 31. The belt cleaning device 36 and the like are provided for removing and cleaning unnecessary objects such as toner that stays on the image holding surface and adheres to the image holding surface.

The secondary transfer device 35 includes, for example, a contact member such as a secondary transfer roll that is arranged so as to be in contact with an image holding surface portion supported by the secondary transfer backup roll 32d of the intermediate transfer belt 31 and to rotate in a driven manner. A contact type transfer device is adopted. Further, in the secondary transfer device 35, the contact member such as the secondary transfer roll is grounded, and the secondary transfer backup roll 32d has a required secondary transfer bias having a negative polarity which is the same polarity as the charging polarity of the toner. Will be supplied.

The belt cleaning device 36 is arranged so as to come into contact with at least the image holding surface portion of the intermediate transfer belt 31 after the secondary transfer at the opening for cleaning work of the housing, and unnecessary substances such as residual toner on the image holding surface. It is equipped with a cleaning member such as an elastic plate for scraping and cleaning.

The paper feeding device 40 is arranged at a position on the lower side of the intermediate transfer device 30. The paper feed device 40 is a retractable body 41 that is freely attached to the housing 10 and is accommodated in a state in which recording sheets 9 of a desired size, type, etc. are stacked on a loading plate (not shown). It is provided with a delivery device 42 that sends out recording papers 9 one by one from the accommodating body 41 toward the paper feed / transport path. The number of the housing 41 and the sending device 42 is increased or decreased as necessary. Further, the paper feed device 40 manually feeds the recording paper 9 from a paper feed tray (not shown) used in a state of being open to the outside of the housing 10 so as to join the recording paper 9 into a middle portion of the supply transport path (Rt1) described later. It has a paper feed mechanism.

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

The fixing device 50 is arranged at a position on the lower side of the intermediate transfer device 30. The fixing device 50 is a heating means so as to rotate in the direction indicated by the arrow and maintain the surface temperature at a predetermined temperature inside the housing 51 in which the introduction port 51a and the discharge port 51b of the recording paper 9 are formed. A heating rotating body 52 having a roll form or a belt form heated by the above, and a roll form or a belt form having a contact with a predetermined pressure and driven rotation in a state substantially along the axial direction of the heating rotating body 52. A rotating body 53 for compression is installed. In the fixing device 50, the portion where the rotating body 52 for heating and the rotating body 53 for pressurization come into contact with each other is a fixing process section in which the recording paper 9 for holding the toner image is introduced and the fixing process (heating and pressurization) is performed. It is configured.

Further, the image forming apparatus 1 has a supply transport path Rt1 connecting between the paper feed device 40 and the intermediate transfer device 30 as a main paper transport path inside the housing 10, and a secondary transfer of the intermediate transfer device 30. The relay transport path Rt2 that connects the position and the fixing device 50, the discharge transport path Rt3 that connects between the fixing device 50 and the paper discharge port 11 of the housing 10, and the discharge transport path Rt3 that branches downward from the middle of the discharge transport path Rt3. The reversing transport path Rt4 that reverses the front and back of the recording paper 9 and the double-sided transport path Rt5 that branches laterally from the upper part of the reversing transport path Rt4 and transports the recording paper 9 whose front and back are reversed to the supply transport path Rt1. It is provided.

The supply transport path Rt1 is a transport path for transporting and supplying the recording paper 9 sent out from the paper feed device 40 to the secondary transfer position of the intermediate transfer device 30. The supply transport path Rt1 is composed of a plurality of paper transport roll pairs 45a to 45d and a plurality of paper guide members (not shown). The relay transfer path Rt2 is a transfer path for transporting the recording paper 9 after the secondary transfer to the fixing device 50. The relay transport path Rt2 is composed of, for example, an intake type belt transport device 46. The discharge transport path Rt3 is a transport path for transporting the recording paper 9 on which the image is formed after fixing to the discharge accommodating unit 12. The discharge transport path Rt3 is composed of a plurality of discharge roll pairs 47a, 47b, etc. and a paper guide member (not shown). The reversing transfer path Rt4 is composed of a reversing roll pair 48 whose rotation direction can be switched between a normal rotation direction and a reverse rotation direction, and a paper guide member (not shown). The inverted transport path Rt4 is a transport path in which the transport direction of the recording paper 9 is switched from the discharge transport path Rt3 by a switching member (not shown). The double-sided transport path Rt5 is composed of a plurality of paper transport roll pairs 49 and the like and a plurality of paper guide members (not shown).

<Basic image formation operation by the image forming device>
In this image forming apparatus 1, the basic image forming operation described below is performed. Here, an operation in the case of forming a full-color image composed 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 control device 60 receives a request command for an image forming operation from the outside or the like, each photoconductor drum 21 of the four image forming apparatus 20 (Y, M, C, K) has an arrow. Each of them is rotated in the direction indicated by A, and each charging device 22 receives a charging current to generate a contact discharge. As a result, the image-forming surface of each photoconductor drum 21 is charged to a required polarity (for example, a negative polarity) and a potential, respectively.

Subsequently, each exposure apparatus 23 exposes the image-forming surface of each photoconductor drum 21 after charging according to the image signal decomposed into each color component (Y, M, C, K). As a result, an electrostatic latent image of each color component having a predetermined potential is formed on the image forming surface of each photoconductor 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 developing electric field formed between the developing roll 241 and the photoconductor drum 21 under the supply of the developing bias electrostatically applies to the electrostatic latent image portion of each color component on the image forming surface of the photoconductor drum 21. Attach. As a result, toner images of the corresponding colors of the four colors (Y, M, C, K) are individually formed on the image forming surface of each photoconductor drum 21.

Subsequently, each primary transfer device 25 receives the supply of the primary transfer current to form a primary transfer electric field with the photoconductor drum 21, so that the toner image on each photoconductor drum 21 is intermediated in the intermediate transfer device 30. Primary transfer is performed in order (in the order of Y, M, C, K) with respect to the image holding surface of the transfer belt 31. Further, the drum cleaning device 26 cleans the image forming surface of each photoconductor drum 21 after the primary transfer or the like. Further, the static eliminator 27 eliminates static electricity on the image forming surface of each photoconductor drum 21 after the primary transfer, and prepares for the next image forming operation on each photoconductor drum 21.

Next, in the intermediate transfer device 30, the intermediate transfer belt 31 rotates in the direction indicated by the arrow B, so that 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 feed device 40, the paper feed device 42 sends the required recording paper 9 from the accommodating body 41 to the supply transfer path Rt1 and then feeds the required recording paper 9 to the secondary transfer position of the intermediate transfer device 30 via the supply transfer path Rt1. Supply. Then, 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 with the intermediate transfer belt 31, so that the four colors on the intermediate transfer belt 31 are formed. The toner image of is secondarily transferred to one side of the recording paper 9.

Next, the recording paper 9 on which the unfixed toner image is secondarily transferred is transferred to the fixing device 50 via the relay transfer path Rt2 after being peeled from the intermediate transfer belt 31. In the fixing device 50, the recording paper 9 is heated and pressurized when it is introduced into a fixing processing portion which is a contact portion between the heating rotating body 52 and the pressing rotating body 53 and passes therethrough. 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 after the toner image is fixed is discharged from the housing 51 of the fixing device 50 and then transported via the discharge transport path Rt3, and finally from the paper discharge port 11 to the housing 10. It is discharged to the outside of the paper and is housed in the discharge storage unit 12.

Further, when an image is 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 used by a switching member (not shown) from the discharge transport path Rt3 to the reverse transport path Rt4. Transport to. The reverse roll pair 48 of the reverse transfer path Rt4 has the rotation direction changed from the normal rotation direction to the reverse direction while holding the upper end of the transferred recording paper 9, and the recording paper 9 is turned upside down. Is transported to the double-sided transport path Rt5. The toner image is transferred to the back surface of the recording paper 9 conveyed to the double-sided transfer path Rt5 via the supply transfer path Rt1. After that, the recording paper 9 is conveyed to the fixing device 50 via the relay transport path Rt2, is subjected to fixing treatment (heating and pressurization) by the fixing device 50, and is subjected to the fixing process (heating and pressurization), and the discharge accommodating section 12 is conveyed via the discharge transfer 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. Further, when a request command for a plurality of image forming operations is received, the above image forming operation is similarly repeated for the number of images.

In addition, in the image forming apparatus 1, in the above image forming operation, a monochromatic image is formed by operating any one of the four image forming apparatus 20 (Y, M, C, K), and 4 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.

<Structure of characteristic parts 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 at least a sign of abnormality such as wear of the end portion of the image quality guarantee range of the photoconductor drum 21. .. Further, the image forming apparatus 1 has the following configuration as a function of making it possible to identify a plurality of information for knowing a sign of abnormality such as wear of at least the end of the image quality guarantee range of the photoconductor drum 21. There is.

As shown in FIG. 3, the photoconductor drum 21 has an image quality guarantee range 212. Here, the image quality guarantee range 212 is larger than the width of the maximum size recording paper 9 (for example, the width in the lateral direction of A3 size) among the papers that the user is allowed to form an image in the image forming apparatus 1. The range having a wide width, the image quality guarantee range 212, is a region used for forming a normal image (including a borderless image) instructed by the user to the image forming apparatus 1. Further, the photoconductor drum 21 is configured as an image-forming range 210 including the ends 215 and 216 located at both ends on the outer side of the image quality guarantee range 212 along the axial direction D. The ends 215 and 216 of the photoconductor drum 21 have a photoconductor layer made of a photosensitive material on the peripheral surface of a conductive base material. The image-forming range 210 of the photoconductor drum 21 is literally a range in which an image can be formed. However, no image is formed on the ends 215, 216 of the photoconductor drum 21 during normal image formation.

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

By the way, as shown in FIG. 3, the photoconductor drum 21 is charged by contact with the charging roll 221 of the charging device 22. As described above, the charging device 22 is supported in a state where the rotating shaft 223 of the charging roll 221 receives a pressing force F at both ends in the axial direction D. The charged roll 221 in such a supported state has a convex shape as a whole so as to move away from the outer peripheral surface of the photoconductor drum 21 at the central portion thereof and to approach the photoconductor drum 21 at both ends thereof. It bends and bends. Therefore, the photoconductor drum 21 is placed in a state where the left and right ends of the charging roll 221 continue to be in contact with each other at a relatively strong pressure as compared with the central portion.

As a result, as shown in FIGS. 4A and 4B, the photoconductor drum 21 has a portion in which the left and right ends of the charging roll 221 are in strong contact with each other (usually, the outer portion of the image forming range 210). The portion where the pressure contact force is locally increased begins to be worn in a streak-like manner so as to extend in the circumferential direction (reference numeral 219 is a worn portion). Further, as the frequency of use of the photoconductor drum 21 increases, the streaky wear portion 219 is inside (central portion) along the axial direction D as exemplified in FIGS. 4 (c) and 4 (d). It gradually displaces so that it can enter, and it becomes unevenly worn.

That is, as shown in FIG. 4C, the worn portion 219 generated in the photoconductor drum 21 is inserted into the ends 215 and 216 located outside the image quality guarantee range 212 of the image forming range 210. grow up. After that, 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 ends of the image quality guarantee range 212.

In this case, when the worn portion 219 enters the left and right ends of the image quality guarantee range 212, the end wear of the photoconductor drum 21 at the time of the abnormality occurs. Further, the growth rate and the degree of spread of the friction portion 219 may be evenly generated at the left and right ends of the photoconductor drum 21, but may be different at the left and right ends.

The photoconductor drum 21 has a photoconductor layer formed on the peripheral surface of a grounded conductive base material, and functions as a capacitor in which the surface of the photoconductor layer is charged by a charging roll 221 to be 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 functions as a capacitor. The capacitance C (= Q / V) of 21 is locally reduced. Therefore, when the worn portion 219 is present in at least the image forming range 210 of the photoconductor drum 21, the same charge Q is imparted by the charging roll 221 due to the decrease in the capacitance C due to the decrease in the film thickness of the photoconductor layer. Even so, the level of dark attenuation that decreases until the surface potential V of the photoconductor drum 21 moves to the developing position facing the developing roll 241 of the developing device 24 increases. The ratio of the charge potential: Vh of the photoconductor drum 21 to decrease increases in proportion to the increase in the level of dark attenuation of the photoconductor drum 21. As a result, a large amount of toner adheres to the worn portion 219 in the developing process, and the worn portion 219 is visualized as a portion having a higher density than the portion other than the worn portion 219.

Further, in the image forming apparatus 1, as shown in FIG. 5A, the developing potential Vd1 of the developing roll 241 of the developing apparatus 24 is lower than the charging potential Vh1 of the photoconductor drum 21 during normal image forming. The image region whose charging potential has dropped to Vi due to image exposure is reverse-developed by the 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 or absence of the worn portion 219 of the photoconductor drum 21, the developing roll 241 of the developing apparatus 24 is mounted on the photoconductor drum 21. A development potential Vd2 higher than the charge potential Vh1 is supplied. Then, when the worn portions 219 are present at the ends 215 and 216 of the photoconductor drum 21, the charging potential Vh1'of the photoconductor drum 21 is lowered as compared with the region where the other worn portions 219 are not generated, as described above. do. Therefore, in the worn portion 219 of the photoconductor drum 21, the potential difference (Δα1) between the charging potential Vh1'of the photoconductor drum 21 and the developing potential Vd2 of the developing roll 241 is compared with the region where the other worn portions 219 are not generated. ) Becomes larger, and it is visualized as a portion having a higher density than the portion other than the worn portion 219.

In the image forming apparatus 1, the dark image portions K1 and K2 in which the image in which the worn portion 219 is developed in a dark color looks like a streak are along the axial direction of the image quality guarantee range 212 as shown in FIG. Appears on the outside. Therefore, it is usually used as a recording paper 9 in order to transfer and detect the image portions K1 and K2 having a high density that look like streaks near the left and right ends along the axial direction of the photoconductor drum 21 on the recording paper 9. It is necessary to use a special recording paper 9B having a wider width along the axial direction of the photoconductor drum 21 than the standard recording paper 9 of A3 size or the like. The left and right ends of the special recording paper 9B correspond to the ends 215 and 216 outside the image quality guarantee range of the photoconductor drum 21. As the special recording paper 9B, a paper having a width wider than the ends 215 and 216 outside the image quality guarantee range of the photoconductor drum 21 may be used.

The image forming apparatus 1 knows a sign of abnormality such as wear of the end of the image quality guarantee range of the photoconductor drum 21 by executing the first image forming operation without performing image exposure on the special recording paper 9B. It becomes possible. In this first image-forming operation, if the image portions K1 and K2 having a high density that look like streaks are present at the left and right edges of the special recording paper 9B, the worn portion before the original edge wear develops. Since it indicates that 219 is generated in the photoconductor drum 21, the presence of the image portions K1 and K2 can be regarded as a sign of an abnormality called end wear.

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

Therefore, in the image forming apparatus 1 according to the first embodiment, as shown in FIG. 6, an image in which the worn portion 219 is developed to a dark color is formed in the vicinity of the left and right ends of the special recording paper 9B. It is configured to execute the first image-forming operation that outputs the image portions K1 and K2 having a dark density that looks like a shape.

That is, as shown in FIG. 7, the image forming apparatus 1 develops the ends 215 and 216 of the image forming range 210 of the photoconductor drum 21 which are at least other than the image quality guarantee range 212 with a developer. It includes a control means 61 for executing an image forming operation and an output means 70 for outputting information regarding the result of the first image forming operation.

The control means 61 is executed by a CPU (Central Processing Unit) 61a that collectively controls the operation of the image forming apparatus 1, a ROM (Read Only Memory) 61b that stores a program or the like executed by the CPU 61a, and a CPU 61a. It has a RAM (Random Access Memory) 61c for storing parameters and the like used in the program, and a bus and the like (not shown) for connecting the CPU 61a, the ROM 61b, and the like. The control means 61 is configured to perform the above-mentioned first image-forming operation by executing a program stored in the ROM 61b. The control means 61 executes the first image formation operation, and also executes an operation of sequentially storing the image formation conditions and the result of the first image formation operation when the first image formation operation is executed in the ROM 61b. Further, the control means 61 has a timekeeping function and a calendar function, and each time the first image forming operation is executed, the date and time information is added and stored in the image forming condition, the result of the first image forming operation, and the like. It also has a function of appropriately reading out the conditions and results of the first image-forming operation in the past and displaying them on the display unit 14b of the operation display device 14. Although the control means 61 is configured as a part of the central control device 60, it may be configured as an independent control means.

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

As shown in FIG. 7, the control means 61 is a charging voltage feeding means and a developing voltage capable of supplying a charging bias to the charging roll 221 of the charging device 22 and supplying a development bias to the developing roll 241 of the developing device 24. Connected to a power feeding means 15 as an example of the power feeding means, an exposure driving unit 16 for driving the exposure device 23, an output means 70 for outputting the result of the first image forming operation, the display unit 14b of the operation display device 14, and the like. A control signal necessary for performing an operation such as the first image forming operation is transmitted to them. Further, the control means 61 is connected to a communication unit 19 that communicates information with an external device or the like, an input unit 14a of the operation display device 14, and the like, thereby obtaining information necessary for control operation. ing.

Then, when the control means 61 executes the first image forming operation, the end portions 215 and 216, which are outside the image quality guarantee range of the photoconductor drum 21, for at least one of the charging bias and the developing bias supplied from the feeding means 15. Is also configured to change over a plurality of steps to a condition for generating a potential difference Δα that can be developed with a developer (toner) supplied from the developing apparatus 24.

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

Further, when the first image forming operation is executed, the control means 61 controls the operation of the exposure driving unit 16 so as not to perform exposure by the exposure apparatus 23 and to form an electrostatic latent image.

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

In fact, this potential difference Δα is based on the charging potential when forming a normal image: Vh1 (FIG. 5A), and the developing potential when forming a normal image: Vd1 at the end 215, Special development potential when development at 216 is also possible: Generated by changing to Vd2 (FIG. 5 (b)). Further, as the special development potential: Vd2 at this time, for example, as shown in FIG. 5 (b), a potential having a magnitude exceeding the charging potential: Vh1 at the time of image formation of a normal image is an absolute value. Will be adopted. This special development potential: Vd2 is obtained in advance by, for example, conducting an experiment for investigating a development potential suitable for performing the above development by changing various development biases (actually, the voltage of the DC component).

Further, the charging potential: Vh1 and the developing potential: Vd2 control the feeding means 15 based on the signal from the control means 61 when the first image forming operation is executed, so that at least one of the potentials becomes a plurality of values. It can be changed.

As shown in FIG. 5B, the control means 61 has a plurality of stages of the development potential: Vd generated by the DC component of the development bias, for example, when the charge potential: Vh of the photoconductor drum 21 is constant. Change to a large value over. When the difference (absolute value) Δα = | Vh-Vd | between the charge (surface) potential of the photoconductor drum 21 and the development potential: Vd generated by the DC component of the development bias is small, the photoconductor drum 21 is worn. Even if the first image processing operation is executed, such as when the amount of wear of the portion 219 is small, the image portions K1 and K2 having a high density that look like streaks may not appear near the left and right edges of the special recording paper 9B. .. In this case, the photosensitivity is increased by increasing the difference (absolute value) Δα = | Vh-Vd | between the charge (surface) potential of the photoconductor drum 21 and the development potential: Vd generated by the DC component of the development bias. Even when the amount of wear of the worn portion 219 of the body drum 21 is small, it can be developed so that the image portions K1 and K2 having a high density 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 (serviceman) selects and instructs an execution mode of the first image forming operation from the input unit 14a in the operation display device 14. It is configured as. By operating the input unit 14a of the operation display device 14, the service engineer can appropriately set at least one of the charging potential: Vh1 and the developing potential: Vd2 to a desired value.

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

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

The output means 70 having this configuration is an image forming operation when forming a normal image in the first image forming operation executed by the control means 61, except that the development bias is changed and the electrostatic latent image is not formed. It is realized by setting the control contents to be performed according to the conditions in. In the output means 70 having such a configuration, information regarding the result of the first image forming operation is recorded and output on the recording paper 9.

However, the recording paper 9 used at the time of output of the output means 70 needs to be able to transfer the toner image formed by development to the ends 215 and 216 outside the image quality guarantee range of the photoconductor drum 21. Therefore, a special recording paper (paper for confirmation) 9B whose feed width is substantially the same as the axial dimension of the image forming range 210 in the photoconductor drum 21 is used (FIG. 6). 6).

This 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 housing 41 in the paper feeding device 40 and sent out from the sending device 42. Will be supplied. On the other hand, when the special recording paper 9B cannot be supplied from the paper feed device 40, for example, it is stored in a manual feed tray of a manual paper feed mechanism (not shown) and then sent out so as to be merged in the middle of the supply transport path Rt1. It is supplied to the secondary transfer position of the transfer device 30.

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

However, the plurality of special recording sheets 9B ₁ , 9B ₂ to 9B _n output from the image forming apparatus 1 form an image without executing the exposure step by the exposure apparatus 23. Therefore, information for distinguishing each other is not added to the plurality of special recording sheets 9B ₁ , 9B ₂ to 9B _n that are output under different conditions, and can be distinguished from each other by themselves. However, there is a management inconvenience.

Therefore, in the image forming apparatus 1 according to the first embodiment, as shown in FIG. 9, the identification code 100 as an example of the identification information for identifying the information regarding the result of the first image forming operation is used as a special recording sheet 9B. It is configured to include additional means to be added to. As the additional means, the output means 70 is used. The output means 70 is composed of, 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 means 61, and a plurality of special images are formed. It is configured to create and add an image of the identification code 100 that identifies the recording sheets 9B from each other. When the image forming apparatus 20 that executes the first image forming operation is the black (K) image forming apparatus 20K, the image forming apparatus that creates the identification code 100 is an image forming apparatus other than the black (K), for example, cyan. The image forming apparatus 20C of (C) is selected. Further, when the image forming device 20 that executes 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, the yellow is basically the same. The identification code 100 is created by an image forming device other than the image forming device 20Y of (Y). However, since the identification code 100 formed by the image forming apparatus 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. It may be difficult to read. Therefore, when the first image forming operation is executed by the yellow (Y) image forming apparatus 20Y, a margin 101 is provided at the front end or the rear end of the recording paper 9 as shown in FIGS. 11A and 11B. It is desirable to control the start end or end end of the first image formation operation so as to form.

The control means 61 identifies in the image forming apparatus 20 that does not execute the first image forming operation when the first image forming operation is executed by making at least one of the charging potential: Vh1 and the developing potential: Vd2 different. An image of reference numeral 100 is created and formed on the corresponding special recording paper 9B. The image information of the identification code 100 is created by the control means 61.

The identification code 100 may be various as long as it can distinguish a plurality of special recording sheets 9B from each other, such as a one-dimensional bar code, a two-dimensional bar code, or a visually readable code such as a number or a character. Things can be used. In the illustrated embodiment, as shown in FIG. 10, a two-dimensional bar code is used as the identification code 100. Further, as the identification code 100, as shown in FIG. 11C, a two-dimensional bar code and a plurality of codes consisting of numbers and characters such as sample 1 and sample 2 may be included. The QR code (registered trademark) as an example of a two-dimensional bar code has a maximum amount of information of 7,089 characters for numbers only, 4,296 characters for alphanumerical characters, and 1,817 characters for kanji and kana characters. are doing.

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

Further, 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, a surface that is the same as the surface that forms the image by the first image formation operation or a surface that is different from the surface that forms the image by the first image formation operation is selected. When the same surface as the surface forming the image is selected as the specific area by the first image forming operation, the specific area is set to, for example, a place where the dense image portions K1 and K2 that look like streaks to be detected do not appear. To. The image portions K1 and K2 having a high streak density tend to appear at both ends 215 and 216 other than the image quality guarantee range 212 along the axial direction of the photoconductor drum 21. Therefore, it is desirable to set the specific area within the image quality guarantee range 212 of the photoconductor drum 21.

Further, the control means 61 has information on the result when the first image forming operation is previously executed in the ROM 61b. Therefore, the control means 61 refers to the information regarding the result when the first image forming operation is executed before stored in the ROM 61b, so that the presence / absence of the occurrence of the dense image portions K1 and K2 and the high density are obtained. Information on the location where the image portions K1 and K2 are generated can be acquired. The control means 61 acquires information on the locations where the dense image portions K1 and K2 are generated, so that the dense image portions K1 and K2 to be detected do not appear even outside the image quality guarantee range 212. The identification code 100 is formed.

Further, as shown in FIG. 12, the surface different from the surface on which the image is formed by the first image formation operation is special when the surface on which the image is formed by the first image formation operation is the first surface (surface). This is the second side (back side) of the recording paper 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 drawing operation, and a special image is formed. An image of the identification code 100 will be formed on the back surface of the recording paper 9B. In this case, images are formed on both the front and back sides of the special recording paper 9B. When the identification code 100 is formed on a surface different from the surface on which the image is formed by the first image forming operation, the image forming apparatus forming the identification code 100 is an image forming apparatus other than the image forming apparatus that executes the first image forming operation. It is not limited to, and can be arbitrarily selected. As the image forming apparatus for forming the identification code 100, the same image forming apparatus as the image forming apparatus for executing 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 the characteristic part of the image forming apparatus (first image formation operation)>
In the image forming apparatus 1, when the service engineer selects and instructs the execution mode of the first image forming operation from the input unit 14a of the operation display device 14, the control means 61 executes the following first image forming operation. To.

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. Executed multiple times. Here, the first image-forming operation when the image-forming device 20K of black color K is operated and executed as a representative will be described.

When it is time to execute the first image processing operation, in the image processing device 20K, the image forming range 210 of the rotating photoconductor drum 21 is charged by the charging device 22 so that the charging potential is the same as that at the time of normal image formation: Vh1. After that, it passes through the developing device 24K to which the developing bias for the first image formation operation is supplied, and the development is performed without receiving the exposure of the exposure device 23.

At this time, as shown in FIG. 5B, the photoconductor drum 21 in the image processing apparatus 20K is charged so that the image forming range 210 has a negative polarity charging potential: Vh1, while the first. A development bias for image formation operation is supplied to confront the development roll 241 of the developing apparatus 24K showing a special development potential: Vd2 having a charge potential: a negative polarity having a magnitude exceeding Vh1.

As a result, a potential difference: Δα1 (= Vd2-Vh1) for developing the ends 215 and 216 outside the image quality guarantee range of the photoconductor drum 21 is generated between the photoconductor drum 21 and the developing roll 241. For example, when "-550V" is applied as the charging potential: Vh1 and "-600" is applied as the special developing potential: Vd2, the potential difference: Δα1 becomes “50V” in absolute value.

As a result, the photoconductor drum 21 is developed with black toner charged in a negative polarity over the entire area of the image forming range 210 including the ends 215 and 216 outside the image quality guarantee range.

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

As a result, the first image drawing 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 developing potential: Vd2 of the photoconductor drum 21.

As a special development potential, as long as a potential difference that can develop the ends 215 and 216 outside the image quality guarantee range of the photoconductor drum 21 can be obtained, the two-dot chain line is illustrated in FIG. 5 (b). It is also possible to apply a developing potential: Vd3, which is a potential just before the charging potential: Vh1 at the time of normal image formation. The potential difference at this time is Δα2.

When such a special developing potential: Vd3 is adopted when the level of dark attenuation of the worn portion 219 in the photoconductor drum 21 is relatively large, the developing potential Vd3 (potential difference Δα2) also develops the worn portion 219. This is especially effective.

Further, in the first embodiment, since the ends 215 and 216, which are outside the guaranteed image quality range of the photoconductor drum 21, are also developed in the first image forming operation, the development current supplied from the power feeding means 15 can be used for the development. 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 a charging bias supplied from the feeding means 15 while keeping the developing current at the value of the developing bias when forming a normal image. It may be modified and configured to correspond. In addition to this, in the first image forming operation, both the development bias and the charging bias may be changed (adjusted) so as to generate the potential difference Δα1 (Δα2) so as to correspond to each other.

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

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

Then, when this first image drawing operation is executed, the service engineer looks at and examines the image on the special recording paper 9B finally output. This allows the service engineer to know at least whether or not there is a sign of abnormality such as wear of the end portion of the image quality guarantee range of the photoconductor drum 21 (end wear).

That is, as shown in FIGS. 6 and 9, an image is formed on the output special recording paper 9B in a state where the toner is substantially uniformly adhered to the entire one side thereof.

At this time, it extends in a streak pattern near the left and right ends of the width direction W substantially orthogonal to the transport direction E of the special recording paper 9B after output, for example, along the transport direction E as illustrated in FIG. When it is confirmed that the image portions K1 and K2 having a high visible density are present, it can be known that there is a sign that an abnormality called end wear of the photoconductor drum 21 occurs.

On the other hand, if the presence of the high-density image portions K1 and K2 that appear to be streaks is not confirmed near the left and right ends of the special recording paper 9B after output, it is said that the end of the photoconductor drum 21 is worn. It is possible to know that there is no sign that an abnormality will occur.

Further, when the service engineer confirms the presence of the dense image portions K1 and K2 that appear to be streaks on the left and right ends of the special recording sheet 9B by the first image forming operation, the service engineer confirms the presence of the edges on the photoconductor drum 21. It is judged that it is a sign of an abnormality called partial wear, and an arrangement is made to replace the photoconductor drum 21 in which the presence of the image portions K1 and K2 is confirmed with a new photoconductor drum, or a new photoconductor is used. 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 photoconductor drum 21. Further, by preventing the occurrence of image defects due to the edge wear, the image forming apparatus 1 cannot be used during the work of identifying and repairing the cause of the image defects (unusable time (unusable time). It is also possible to prevent the occurrence of downtime).

In the first embodiment, as shown in FIG. 9, the identification codes 100 corresponding to the plurality of special recording sheets 9B ₁ , 9B ₂ , ... 9B _n output by the first image forming operation are respectively. Will be added. Therefore, the service engineer can visually read the identification code 100 consisting of character information such as "Sample 1" or read the identification code 100 consisting of a two-dimensional bar code with a bar code reader to obtain a plurality of special sheets. Recording sheets 9B ₁ , 9B ₂ , ... 9B _n can be distinguished from each other. As the barcode reader, a smartphone or the like having a barcode reading function possessed by a service engineer may be used.

As the information identified by the identification code 100, the identification information of the photoconductor drum 21, the charging potential of the photoconductor drum 21: the value of Vh1, the developing potential of the developing device 24: the value of Vd2, and the first image forming operation were executed. It is possible to know the environmental conditions such as temperature and humidity in the image forming apparatus 1 at that time, and to manage the output of a plurality of special recording sheets 9B ₁ , 9B ₂ , ... 9B _n by distinguishing them from each other. 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 relates to the first embodiment except that a configuration capable of executing a second image forming operation by the control means 61 is added as a function of knowing a sign of an abnormality related to at least a part of the parts. It has the same configuration as the image forming apparatus 1.

<Function to know the sign of abnormality of parts>
The image forming apparatus 1 according to the second embodiment is added to the configuration related to the first image forming operation as a function for knowing at least a sign of abnormality such as wear of the end portion of the image quality guarantee range 212 in the photoconductor drum 21. It has the following configuration. Further, the image forming apparatus 1 has a function of making it possible to identify a plurality of information for knowing a sign of abnormality such as wear of at least the end portion of the image quality guarantee range 212 in the photoconductor drum 21.

That is, in this image forming apparatus, as shown in FIGS. 3 and 13, the control means 61 in the first embodiment charges the image forming range 210 of the photoconductor drum 21 with the charging device 22 and uses a developing agent. It is configured to be able to perform a second image forming operation including an operation of developing and an operation of developing the image forming range 210 of the photoconductor drum 21 with a developer without being charged by the charging device 22. Further, in this image forming apparatus, the output means 70 in the first embodiment is configured to be able to output information regarding the result of the second image forming operation, as shown in FIG. The former operation (the operation of charging the image forming range 210 of the photoconductor drum 21 with the charging device 22 and developing with the developer) in the second image forming operation corresponds to the first image forming operation. Can be treated as being.

When the control means 61 executes the second image forming operation (the former and the latter operations), the control means 61 switches whether or not to supply the charge bias from the power supply means 15 (supply or non-supply), and also supplies the power supply means. The development bias supplied from 15 is configured to be changed so that the image-forming range 210 of the photoconductor drum 21 can generate a potential difference (Δα) that can be developed by the developer. Further, when the second image forming operation is executed, the control means 61 controls the operation of the exposure driving unit 16 so as not to perform the exposure by the exposure apparatus 23 and to form the electrostatic latent image.

First, when the former operation (actually, the first image forming operation) of the second image forming operation is executed, the control means 61 is the power feeding means 15 as in the case of the first image forming operation in the first embodiment. As shown in FIG. 13A, the edges 215 and 216 outside the image quality guarantee range of the photoconductor drum 21 can also be developed with the developing agent supplied from the developing apparatus 24. It is configured to change to the condition for generating the potential difference Δα.

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

Next, when the latter operation of the second image forming operation is executed, the control means 61 stops (non-supplies) the supply of the charging bias from the feeding means 15 as illustrated in FIG. 13 (b). The image-forming range 210 of the photoconductor drum 21 is not charged (charging potential: Vh2 = 0), while the development bias can be developed in the image-forming range 210 of the photoconductor drum 21. Potential difference: Δα3 is obtained. Change to the current that can be used. As the special developing potential: Vd4 at this time, a value at which the potential difference Δα3 becomes substantially the same as the potential difference Δα1 at the time of the first image formation operation is adopted.

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

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

The output means 70 is, for example, a developer image (unfixed toner image) formed on the photoconductor drum 21 by the second image formation operation, as in the case of the output means 70 for the first image formation operation in the first embodiment. ) Is transferred to the recording paper 9 and output. However, the recording paper 9 used for this output has a feed width substantially the same as the axial dimension of the image forming range 210 in the photoconductor drum 21, as in the case of outputting the result of the first image forming operation. A special recording sheet 9B, which is treated as an exception, is used (FIG. 14).

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

Further, the second image forming operation is also 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, the first image forming operation when the black color K image forming apparatus 20K is operated and executed will be described.

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

At this time, the photoconductor drum 21 in the image forming apparatus 20K is charged so that the image forming range 210 has a negative polarity charging potential: Vh1, while the developing current for the first image forming operation is supplied. Charging potential: Confronts the developing roll 241 of the developing apparatus 24K showing a special developing potential: Vd2 consisting of a negative polarity having a magnitude exceeding Vh1.

As a result, as shown in FIG. 13A, there is a photosensitivity between the charging potential: Vh1 in the image forming range 210 of the photoconductor drum 21 and the special developing potential: Vd2 generated in the developing roll 241. A potential difference: Δα1 is generated that also develops the ends 215 and 216 outside the guaranteed image quality range of the body drum 21. As a result, the photoconductor drum 21 is developed with black toner charged in a negative polarity over the entire area of the image forming range 210 including the ends 215 and 216 outside the image quality guarantee range.

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

As a result, the first image drawing operation by the operation of the image forming device 20K is completed. Further, this first image forming operation is similarly executed by sequentially operating the image forming devices 20 (Y, M, C) of colors other than the black color independently.

By executing this first image formation operation (the former operation in the second image formation operation), a special recording sheet 9B for four colors (Y, M, C) in which the result of the image formation operation is recorded is obtained. Can be done (Fig. 14).

At this point, as in the case where the first image forming operation in the first embodiment is described, at least the edge of the photoconductor drum 21 is examined by the service engineer by looking at the output image on the special recording paper 9B. It is possible to know whether or not there is a sign of an abnormality called partial wear. That is, the density appears to extend in a streak along the transport direction E as illustrated in FIG. 14 near the left and right ends of the width direction W substantially orthogonal to the transport direction E of the special recording paper 9B after output. When the dark image portions K1 and K2 are present, it can be known that there is a sign that an abnormality such as end wear of the photoconductor drum 21 occurs.

However, as illustrated in FIG. 14, 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 has a different density from that of the image portions K1 and K2. The image portion K3 may be present.

In this case, it is difficult to determine that the presence of the image portion K3 alone is a sign of another abnormality other than the end wear of the photoconductor drum 21. In particular, when the image portion K3 is periodically present at substantially the same interval along the transport direction E of the special recording paper 9B, the image portion K3 is present at a portion different from the image portions K1 and K2. Since the image results have different configurations, it cannot be determined that at least it is a sign that an abnormality such as end wear of the photoconductor drum 21 occurs. The second image formation operation (the latter operation described above) becomes effective when executed in such a case.

Next, at the time of executing the latter operation in the second image processing operation, in the image processing device 20K, the image forming range 210 of the rotating photoconductor drum 21 is not charged by the charging device 22, and the next exposure device 23 is used. After passing through without receiving the exposure of the above, development is performed by passing through the developing apparatus 24K to which the developing current for the second image forming operation is supplied.

At this time, as shown in FIG. 13B, the photoconductor drum 21 of the image processing apparatus 20K is in a state of charging potential: Vh2 = 0 without charging the image forming range 210, while the first one. 2 A developing current for image-forming operation is supplied to confront the developing roll 241 of the developing apparatus 24K showing a special developing potential: Vd3 having a negative potential larger than the charging potential: Vh2 = 0.

As a result, between the charging potential of the image forming range 210 of the photoconductor drum 21: Vh2 = 0 and the special developing potential: Vd4 generated on the developing roll 241, the image quality of the photoconductor drum 21 is out of the guaranteed range. A potential difference: Δα3 that can also develop the ends 215 and 216 is generated. For example, when "-50" is applied as a special developing potential: Vd4 with respect to the charging potential: Vh2 = 0, the potential difference Δα3 becomes “50V” in absolute value. This potential difference Δα3 is the same as the potential difference Δα1 applied during the first image formation operation. As a result, the photoconductor drum 21 is developed with black toner charged in a negative polarity over the entire area of the image forming range 210 including the ends 215 and 216 outside the image quality guarantee range.

Subsequently, the black toner image formed on the photoconductor drum 21 during the second image formation operation is first transferred to the intermediate transfer belt 31 of the intermediate transfer device 30 and conveyed, and then special recording is performed at the secondary transfer position. Secondary transfer is performed on paper 9B. Finally, the black toner image during the second image drawing operation is fixed on the special recording paper 9B by the fixing device 50, and then output to the discharge accommodating unit 12 in a state of being recorded on the special recording paper 9B. ..

As a result, the latter operation in the second image forming operation by the operation of the image forming apparatus 20K is completed. The operation described later in this second image forming operation is similarly executed by sequentially operating the image forming devices 20 (Y, M, C) of colors other than the black color independently.

Then, even when the latter operation in the second image forming operation is executed, the special recording paper 9B is finally output and can be obtained. At this time as well, the service engineer can know whether or not there is another sign of abnormality in addition to the sign of abnormality such as end wear of the photoconductor drum 21 by examining the image on the special recording paper 9B. can.

That is, at this time, as illustrated in FIG. 15, if the special recording paper 9B does not have the dense image portion K3 that was present at the end of the first image forming operation, the image portion K3 is present. It is considered that the image disappears because the charging device 22 does not charge the image, and it can be known that there is a sign of abnormality such as damage or functional deterioration that causes a part of the charging roll 221 to form the image portion K3.

This is within the image forming range 210 of the photoconductor drum 21 charged in the damaged or functionally deteriorated portion when the damaged or functionally deteriorated portion causes charging failure in a part of the charging roll 221. The charging potential of the portion: Vh becomes a lower potential than that of the other portions, and the potential difference from the developing potential: Vd also becomes relatively large. As a result, the portion where the charge potential of the photoconductor drum 21 is lowered becomes easy to develop and a large amount of toner adheres to the photoconductor drum 21, and the image portion K3 is formed and visualized corresponding to the portion. are doing.

At this time, if the period (interval) of the image portion K3 has a dimension corresponding to the length (circumference) of the outer circumference of the charging roll 221, the image portion K3 is damaged in a part of the charging roll 221. It is more likely that the information is a sign of an abnormality called functional deterioration. Therefore, when such a result is obtained, the service engineer can take measures to promptly replace the corresponding charging device 22 (charging roll 221) with a new one.

On the other hand, if the special recording paper 9B (FIG. 15) output at this time also contains the dense image portion K3 (FIG. 14) that was present at the end of the first image drawing operation, It can be inferred that damaged or functionally deteriorated portions occur at substantially the same intervals in the circumferential direction within the image quality guarantee range of the photoconductor drum 21. In this case, a normal charging potential cannot be obtained in a portion where the photoconductor drum 21 is damaged or its function is deteriorated, and there is a high possibility that an image defect due to the normal charging potential will occur. Therefore, when such a result is obtained, the service engineer can take measures to replace the corresponding photoconductor drum 21 with a new one as soon as possible.

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

Further, as illustrated in FIG. 14, another image portion K4 having a wider interval along the transport direction E than the image portion K3 is printed on the special recording paper 9B output when the first image drawing operation is executed. Can appear.

In this case, if the distance between the image portions K4 is such that the distance between the image portions K4 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 photoconductor drum 21. It can also be inferred that this is a result of damage or functional deterioration that occurs at the same intervals.

However, even in this case, as illustrated in FIG. 15, the special recording paper 9B output when the latter operation in the second image forming operation is executed following the first image forming operation is shown on the special recording paper 9B. If it can be confirmed that the image portion K4 still appears, it is possible to know with further certainty that there is a sign of abnormality such as damage or functional deterioration in a part of the photoconductor drum 21 within the image quality guarantee range.

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

Explaining that the same parts as those of the first embodiment are designated by the same reference numerals, the image forming apparatus 1 has one inside the housing 10 unlike the first embodiment, as shown in FIG. It is a monochrome image forming apparatus provided only with an image forming apparatus 20.

In the image forming apparatus 1, during normal image forming, as shown in FIG. 17A, the peripheral surface of the photoconductor drum 21 is charged to a required potential Vh by the charging apparatus 22, and the developing apparatus 24 is developed. The required development bias potential Vd is applied to the roll 241. The exposed portion of the potential Vi formed by image exposure on the peripheral surface of the photoconductor drum 21 is a toner that is reverse-developed according to the development potential which is the potential difference (Vd-Vi) from the development bias potential Vd of the development roll 241. Is visualized by.

Further, during the second image processing operation, the control means 61 sets the charging potential of the photoconductor drum 21 without applying a charging bias to the charging roll 221 of the charging device 22, for example, as shown in FIG. 17 (b). The voltage is set to 0V, and the development roll 241 of the developing apparatus 24 is controlled to supply a development bias Vd5 of about -50V. The peripheral surface of the photoconductor drum 21 moves to the developing region facing the developing roll 241 of the developing device 24 as the photoconductor drum 21 rotates. At this time, the potential of the photoconductor drum 21 is 0 V, whereas when it is supplied to the developing roll 241 of the developing apparatus 24, the development bias is about −50 V, which is relatively relative to the potential of the photoconductor drum 21. It has a low potential. Therefore, the negatively charged toner held on the surface of the developing roll 241 moves to the photoconductor drum 21 side according to the potential difference between the photoconductor drum 21 and the developing roll 241 of the developing device 24, and the photoconductor drum 21 Toner adheres to the peripheral surface of the paper substantially uniformly and is subjected to bias development. As shown in FIG. 18A, the toner image developed on the peripheral surface of the photoconductor drum 21 is transferred to a special recording paper 9B by the transfer device 25, fixed by the fixing device 50, and then discharged and stored. It is housed in part 12.

Further, the control means 61 changes the value of the development bias supplied to the development roll 241 of the developing apparatus 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 image forming apparatus 1 is developed by the control means 61 at the rear end portion of the special recording paper 9B. The development bias Vd5 supplied to the roll 241 is turned ON / OFF according to the identification information or changed to a different value Vd6, and the identification code 100 having a density different from that of the image of the second image formation operation at the rear end of the special recording paper 9B. Is configured to be added.

As a result, as shown in FIG. 18B, an identification code 100 composed of a one-dimensional barcode indicating an execution condition of the second image formation operation and the like is formed on the rear end portion of the special recording paper 9B. .. Here, the identification code 100 is not limited to the one-dimensional barcode according to the standard, and if the shades of the images are arranged one-dimensionally and can be distinguished from each other, the spacing and width of the shade images may be set. Of course, it can be set freely.

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

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

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

Further, 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, but in the third embodiment, the control means The 61 may be configured to automatically execute the first image drawing operation according to the total number of prints on 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 normally used by the user, but the control means 61 performs the first image forming operation on the display unit of the operation display device 14. It is possible to execute this by urging the user to accommodate the special recording paper 9 in the accommodating section.

In the third embodiment, the case where the development bias of the developing apparatus 24 is switched to form the identification code 100 without charging the peripheral surface of the photoconductor drum 21 has been described, but as described in the first embodiment. In the case of bias development in which the development bias Vb with respect to the charged potential Vh of the photoconductor drum 21 is controlled, the image of the identification code 100 may be formed by exposure by the exposure apparatus 23. In this case, the exposure amount by the exposure apparatus 23 is used to form a normal image so that the development potential becomes too high as in the case of normal image formation and the image density associated with the first image forming operation becomes excessive. It is desirable to lower the time or control the development bias Vb.

In the third embodiment, the case where the development bias of the developing device 24 is switched to form the identification code 100 has been described. However, the primary transfer bias of the transfer device 25 or the secondary transfer device 35 of the secondary transfer device 35 in the first embodiment has been described. The transfer bias may be controlled by the control means 61 as shown in FIG. 17 (c) to form the identification code 100.

[Other embodiments]
In the first and second embodiments, as the output means 70, for example, an output means 70 having another configuration shown below may be applied. The output means 70 includes reading means 72 that reads 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. It is composed of an output unit 75 for output.

As the reading means 72, for example, a line-type density sensor having a reading surface over the entire width direction of the intermediate transfer belt 31 and capable of individually reading a toner image of four colors is applied. As illustrated in FIG. 1, the reading means 72 passes through all of the image forming devices 20 (Y, M, C, K) of the intermediate transfer belt 31 and reaches the image holding surface (the image holding surface) up to the secondary transfer position. It is arranged at a position facing the outer peripheral surface) 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 read information after or immediately after storing the read information. As such an output unit 75, for example, one that is output to the display unit 14b of the operation display device 14 and displays the read information can be applied. In this case, for example, the position and shading of the toner image secondarily transferred to the intermediate transfer belt 31 are displayed on the display unit 14b.

When the output means 70 composed of the reading means 72 and the output unit 75 is adopted, the service engineer displays the operation display device 14 regarding the results when the first image drawing operation and the second image drawing operation are executed. It can be easily confirmed by looking at the contents displayed in the part 14b. Also in this case, by looking at the presence / absence of the above image portions K1 and K2 and the presence / absence of other image portions K3, K4, etc. in the displayed image, is there at least a sign of abnormality such as end wear in the photoconductor drum 21? You can know whether or not.

Incidentally, when outputting this read information, the toner image transferred on 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 in this way, 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.

Further, in the first and second embodiments, when the first image forming operation and the second image forming operation are executed, the control means 61 increases or decreases the potential difference Δα with respect to the developing current and the charging current supplied from the feeding means 15. A configuration may be adopted in which the current is controlled so as to be changed and supplied. When this configuration is adopted, the density difference of the image obtained by executing the first image forming operation and the second image forming operation is adjusted to identify the image part (K1, K2, etc.) showing a sign of abnormality. Can be made easier.

Further, in the second embodiment, when the former operation in the second image forming operation is executed, the charged photoconductor drum 21 is exposed to the exposure device 23 as illustrated by the alternate long and short dash line in FIG. 13 (a). It may be configured to perform exposure to form an electrostatic latent image within the guaranteed image quality range. In this case, as the electrostatic latent image, for example, a latent image of a halftone (intermediate density) image using a screen can be applied. When the electrostatic latent image is formed in this way, the former operation in the second image formation operation has a configuration different from that of the first image formation operation (when the electrostatic latent image is not formed).

Further, the image forming apparatus is limited to the image forming apparatus 1 adopting the intermediate transfer method exemplified in the first and second embodiments as long as it is an image forming apparatus including a photoconductor, a contact type charging device, and a developing apparatus. However, it may be an image forming apparatus of another type.

When an image forming apparatus that does not adopt the intermediate transfer method is applied, the reading means 72 in the output means 70 reads the toner image formed on the photoconductor during the first image forming operation and the second image forming operation. Become.

In the above embodiment, the contact type charging device is mainly described as the charging device, but the uneven wear of the photoconductor is also generated by a cleaning blade or the like for cleaning the surface of the photoconductor, and is of the contact type. Of course, it is not limited to the charging device.

1 ... Image forming apparatus 9 ... Recording paper (example of recording medium)
9B ... Special recording paper (an example of recording medium)
14b ... Display unit (example of display means)
21 ... Photoreceptor drum (example of photoconductor)
31 ... Intermediate transfer belt (an example of an intermediate transfer body)
22 ... Charging device 24 ... Developing device 61 ... Control means 70 ... Output means 72 ... Reading means 75 ... Output unit 210 ... Image formable range 215, 216 ... Ends outside the image quality guarantee range Δα ... Potential difference

Claims (3)

An image holding means having an image quality guarantee range within the image forming range,
A charging means for charging at least an image forming range of the image holding means, and a charging means.
A developing means for developing an electrostatic latent image formed in the image holding means with a developing agent,
A control means for executing the first image forming operation of developing at least an end portion of the image forming range of the image holding means that is out of the image quality guarantee range with a developer.
An output means for outputting information regarding the result of the first image formation operation, and
An additional means for adding identification information that identifies information regarding the result of the first image formation operation to the image imaged by the first image formation operation , and
A developing voltage feeding means capable of supplying a developing voltage to the developing means, and a developing voltage feeding means.
Equipped with
The additional means is an image forming apparatus that adds the identification information by switching the supply and non-supply of the development voltage supplied from the development voltage feeding means or the value of the development voltage . An image holding means having an image quality guarantee range within the image forming range,
A charging means for charging at least an image forming range of the image holding means, and a charging means.
A developing means for developing an electrostatic latent image formed in the image holding means with a developing agent,
A control means for executing the first image forming operation of developing at least an end portion of the image forming range of the image holding means that is out of the image quality guarantee range with a developer.
An output means for outputting information regarding the result of the first image formation operation, and
An additional means for adding identification information that identifies information regarding the result of the first image formation operation to the image imaged by the first image formation operation , and
A transfer means for transferring an image held by the image holding means to an intermediate transfer body or a recording medium, and a transfer means.
A transfer voltage feeding means capable of supplying a transfer voltage to the transfer means,
Equipped with
The additional means is an image forming apparatus that adds the identification information by switching between supply and non-supply of the transfer voltage supplied from the transfer voltage feeding means or the value of the transfer voltage. A plurality of image forming means having the image holding means, the charging means, and the developing means,
Equipped with
The image forming apparatus according to claim 1 or 2 , wherein the additional means adds identification information by using the image forming means that does not execute the first image forming operation.

Images