JP2006011266A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain transferability and fixing properties which will not be influenced by the quality of paper, and to appropriately cope with the situation, when the paper quality is different from the one set in an image forming apparatus. <P>SOLUTION: When an output medium is transported to a 2nd transfer part 210 for transferring an image formed on an intermediate transfer body belt 136 to a printing paper, an output current detection part 234 detects a transfer bias state in a non-image part at an edge part. A decision part 236 decides the paper quality and whether the paper quality is the same as the one set by a user from the result of detection. The decision part 236 adjusts the fixing temperature and transporting speed, by controlling a printing operation mechanism part 340, based on the result of the decision. When the decision part 236 decides that the result of detection is abnormal, an abnormality-countering processing part 260 performs processings to cope with the occurrence of the mismatch of the paper quality as storing an abnormality history in a storage part 262, informing the user of the abnormality information by an informing part 264 or stopping image forming processing via a stop control part 266. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming method and an image forming apparatus for forming an image on a predetermined output medium such as a printer, a copying machine, a facsimile machine, or a multifunction machine having the functions thereof. More specifically, an image (usually referred to as a toner image) obtained by forming a latent image on an image carrier and developing it by an electrophotographic method or an electrostatic recording method is transferred to an output medium as a transfer material. The present invention relates to a technique for forming an image by applying and transferring.

  For example, a printer device, a copying device, a facsimile device, a copying device, or a multi-function device having a plurality of these functions, and the like, after performing desired image processing on the input image, a predetermined output image corresponding to this image is output. There is an image forming apparatus that forms on a medium.

For example, in the case of an image forming apparatus that supports color output, RGB (or Lab (correctly L ^* a ^* b ^* )) image data obtained by reading a document is used as a color suitable for subtractive color mixing according to the output side. Convert to signal. For example, at least three (preferably four) from the Lab color system represented by the Lab signal, for example, the YMC color system represented by each color signal of yellow (Y), magenta (M), and cyan (C) Mapping processing to a system or a CMYK color system with black (K) added thereto generates raster data that has been color-separated for print output. This raster data is sent to a print engine that forms an image corresponding to the read original image on the printing paper. The print engine forms an image on printing paper of a predetermined size based on the received raster data.

  On the other hand, in recent years, color image forming apparatuses such as color printers and color copiers are required to improve the output image quality. There are various factors that affect the image quality, and the type (material, thickness, etc.) of the transfer material as the output medium is one of them.

  Examples include plain paper, thick paper, glossy paper, and transparent printing paper (hereinafter referred to as OHP) for overhead projectors.

  Even if image formation is performed on such various transfer materials under the same image forming conditions, the toner image formed on the transfer material changes in color according to the type of transfer material, There is also a difference in fixing performance, and in some cases, residual toner is burned out, leading to a failure of the fixing unit.

  Therefore, it is conceivable to provide a dedicated sensor (paper quality sensor) for detecting the type of transfer material and to control the image forming conditions based on the detection result in order to perform an appropriate process according to the type of transfer material. However, in this case, there is a problem that the cost is increased by providing the dedicated sensor.

  Therefore, as one method for solving this problem, for example, in Patent Document 1, a constant current value before passing paper is passed through a transfer roller, and a voltage generated at that time is calculated by putting it in a predetermined control equation. In addition to a transfer control method that detects the impedance of the transfer system before passing through a bias control method (PTVC control method: Programmable Transfer Voltage Control), etc., and applies a transfer voltage that allows a current in the proper range to flow. Then, the transfer material resistance value is detected by monitoring the change of the transfer current value immediately after the transfer material front end is inserted into the transfer nip portion, which is the pressure nip portion between the image carrier and the transfer member, and based on the result. Thus, a mechanism for obtaining a good image with any transfer material having any resistance value by correcting the transfer voltage has been proposed.

JP 2001-109281 A

  However, in the mechanism described in Patent Document 1, there is a cycle called “Setup” that is performed at a specific timing in order to realize constant voltage transfer. Specifically, primary charging is performed. When the bias transfer roller comes into contact with the portion, the current is monitored from the timing when the leading edge of the paper reaches the bias transfer roller, and the resistance value of the paper is detected, and the transfer output is corrected based on the result. It has become.

  For this reason, even when a paper quality different from the paper quality specified by the user is set in the apparatus, the printing process is actually performed, and an image abnormality due to a transfer failure or a fixing failure may occur. There is. In particular, the latter may appear as a phenomenon in which unfixed toner remains on the fixing roller and is fixed as a background image in the output image of the next job, which is a problem in terms of concealing information and is a failure due to burn-in. Also causes.

  The present invention has been made in view of the above circumstances, and in the case of dealing with various types of transfer materials, without using a dedicated sensor, transferability and fixability that are not affected by paper quality can be obtained, or The purpose is to propose a mechanism that can take appropriate measures when the paper quality is different from the set paper quality.

  According to the first image forming method of the present invention, a latent image is formed on an image carrier, and an image obtained by developing the latent image is transferred onto a transfer material. An image forming method for forming an image thereon, wherein an image formed on an image carrier is contact-transferred to a transfer material at a transfer portion, and then the image formed on the transfer material is fixed at a fixing portion. At this time, the transfer bias state in the transfer portion in a predetermined period after the transfer material reaches the transfer portion is detected, and the image forming conditions related to the fixing process are controlled based on the detection result.

  Further, the second image forming method according to the present invention forms a latent image on the image carrier and transfers the image obtained by developing the latent image onto the transfer material, so that an output as a transfer material is obtained. An image forming method for forming an image on a medium, wherein when an image formed on an image carrier is contact-transferred to a transfer material at a transfer portion, the transfer material reaches a predetermined period after reaching the transfer portion. When the transfer bias state in the transfer portion is detected and exceeds a predetermined normal range, an abnormality handling process is performed in response to the abnormal transfer material.

  A first image forming apparatus according to the present invention is an apparatus suitable for carrying out the first image forming method according to the present invention, and forms a latent image on an image carrier, and the latent image is An image forming apparatus that forms an image on an output medium, which is a transfer material, by transferring an image obtained by development onto the transfer material, and the image formed on the image carrier contacts the transfer material A transfer unit that transfers, a fixing unit that fixes an image formed on the transfer material, a transfer bias state detection unit that detects a transfer bias state in the transfer unit in a predetermined period after the transfer material reaches the transfer unit, And a control unit that controls image forming conditions related to the fixing process based on the detection result of the transfer bias state detection unit.

  A second image forming apparatus according to the present invention is an apparatus suitable for carrying out the second image forming method according to the present invention, and forms a latent image on an image carrier, and the latent image forming apparatus An image forming apparatus for forming an image on an output medium, which is a transfer material, by transferring an image obtained by developing the image onto a transfer material, wherein the image formed on the image carrier is transferred to the transfer material The transfer bias detection unit detects the transfer bias state in the transfer unit in a predetermined period after the transfer material reaches the transfer unit, and the detection result of the transfer bias state detection unit is within a predetermined normal range. A determination unit that determines whether or not the transfer material exceeds a predetermined normal range, and an abnormality response processing unit that performs a process in response to the abnormality of the transfer material on the condition that the determination unit determines that the predetermined normal range is exceeded It was.

  This second image forming apparatus is more preferably combined with the first image forming apparatus according to the present invention.

  The inventions described in the dependent claims define further advantageous specific examples of the image forming apparatus according to the present invention.

  For example, the image forming apparatus forms a latent image on a first image carrier and develops the image obtained by developing the latent image on a first transfer material (for example, an endless belt). And a second transfer unit for transferring an image transferred onto the second image carrier onto the second transfer material using the first transfer material as a second image carrier. It may have. In this case, the fixing unit fixes the image formed on the second transfer material, and the transfer bias state detection unit performs the second operation for a predetermined period after the second transfer material reaches the second transfer unit. The transfer bias state in the transfer portion is detected.

  Further, it is desirable that the control unit includes a transfer bias control unit that controls a transfer bias in the transfer unit. The transfer bias control unit includes a voltage control unit that controls a transfer output applied to the transfer unit, an output current detection unit that detects an output current value during constant voltage control by the voltage control unit, and an output current. It is preferable to have a transfer output voltage determination unit that determines a transfer output voltage to the transfer unit controlled by the voltage control unit based on the output current value detected by the detection unit.

  The transfer output voltage determination unit transfers the output to the transfer unit based on the constant voltage output value based on whether or not the current value detected by the output current detection unit has reached a desired value and the input calculation result from the output current detection unit. The voltage should be determined.

  The abnormality handling processing unit includes a storage unit that stores a history that the transfer material is abnormal, a notification unit that notifies information that the transfer material is abnormal, or a stop control unit that stops the image forming process. It should be.

  Here, whether or not the transfer material is abnormal is determined by, for example, providing a transfer material type receiving unit that receives the type of the transfer material specified by the user, and the detection result of the transfer bias state detecting unit is the transfer material type receiving unit. May be determined based on whether or not the normal range corresponding to the accepted transfer material type is exceeded.

  According to the first image forming method and the image forming apparatus of the present invention, by detecting the transfer bias state in the transfer portion in a predetermined period after the transfer material reaches the transfer portion, The type is discriminated, and the image forming conditions related to the fixing process are controlled based on the discrimination result.

  Since the type of transfer material is determined using a mechanism that detects the transfer bias state and controls the transfer bias, there is no need to provide a dedicated paper quality detection sensor, and an image related to the fixing process based on the determination result. Since the formation conditions are controlled, by setting appropriate fixing conditions according to the transfer material being used, it is possible to achieve good fixing performance and to prevent the fixing unit from being broken.

  Further, according to the second image forming method and the image forming apparatus of the present invention, it is determined whether or not the transfer bias state as the monitoring result exceeds the normal range. If the transfer bias state exceeds the normal range, the transfer material is abnormal. Therefore, when the transfer material is detected to be abnormal, appropriate abnormality handling processing can be executed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration example when the image forming apparatus according to the present invention is applied to a printer. As shown in the drawing, the standard configuration of the printer 1 (hereinafter referred to as the printer main body 100) includes a main unit 102, an intermediate transfer member belt 136 that is an endless belt that functions as a first transfer material, and a standard discharge tray (CenterTray) 154. And a manual feed tray (SMH) 180 and a first paper feed tray (TRAY1) 190 installed on the lower side of the main unit 102.

  The printer main body 100 can be connected to an external device via a connection cable (not shown) or a network. For example, the connection cable is not illustrated by a CSMA / CD (Carrier Sense Multiple Access with Collision Detection) type LAN (Local Area Network; for example, IEEE802.3) or a Gigabit (Giga Bit) based LAN (hereinafter collectively referred to as a wired LAN). Connected to an image input terminal such as a personal computer.

  The printer main body 100 is not only used as a main body part constituting the printer 1 having a page printer function, but also a copying apparatus having a copying function, a FAX apparatus having a facsimile transmission / reception function, a page printer function, and a copying function. It can also be used as a main part as a so-called multi-function machine having a plurality of functions such as a facsimile transmission / reception function.

  For example, although not shown, a copying apparatus having a copying function can be configured by providing an image reading unit (scanner unit) that reads a document. Or, connect to an image input terminal such as a FAX apparatus or a personal computer via a public switched telephone network (PSTN), an ISDN (Integrated Switched Digital Network), or other communication media including the Internet. Thus, it is possible to configure a FAX apparatus that prints out based on FAX data acquired via the communication interface.

<Basic configuration>
The printer main body 100 uses an electrophotographic image forming process to display an image represented by image forming data (for example, image data read by a scanner or print data input from a personal computer) input from an image input terminal. Then, a visible image is formed (printed), that is, copied on a recording medium such as plain paper or thermal paper. Therefore, the main unit 102 of the printer main body 100 includes a raster output scan (ROS) -based print engine for operating the printer 1 as a digital printing system.

  Inside the main unit 102, recording paper is carried into the ROS-based scanning output system 103 side, or toner cartridges (Toner Cartridge) for each color of the scanning output system 103, Y, M, C, and K are arranged. The standard conveyance comprising various roll members (rotating bodies) 108 and the like for discharging recording paper printed by the cartridge unit 105 and the ROS-based scanning output system 103 to the standard discharge tray 154 and the manual feed tray 180. A system 107 is housed.

  The manual feed tray 180 is provided with various rolls and various paper sensors (manual feed tray paper remaining level sensor 182a, manual feed tray paper presence / absence detection sensor 182b, and manual feed tray level sensor 182c).

  As the roll member 108, for example, a manual feed tray primary feed roll 108a, a manual feed roll pair 108b, a manual take-up roll pair 108c, a resist roll pair (Regi Roll) 108d, a paper take-out roll pair 108e, and the like are provided.

  Although not shown, a tray cabinet, which is an example of a peripheral device that is optionally used in combination with the printer main body 100, can be provided below the standard discharge tray 154.

  A first paper feed tray 190 disposed below the main unit 102 includes various rolls 192 (a pickup roll 192a and a feed roll pair 192b) and various paper sensors 194 (a paper remaining level sensor 194a and a paper presence / absence detection). A feeder unit 196 comprising a sensor 194b) and a paper cassette 198 having a tray table 199 for storing recording papers of a predetermined size (which can also correspond to a plurality of sizes by changing the position of the stopper). It is configured.

  The feeder unit 196 rolls out recording sheets one by one from the sheet cassette 198 and sends them to the standard transport system 107 in the main unit 102.

  The ROS-based scanning output system 103 is an example of a first image carrier, and a drum and photosensitive bias member and a primary bias transfer roll are used to transfer an image onto an intermediate transfer belt that is an example of a first transfer material. Using this intermediate transfer belt as a second image carrier, a transfer image portion of the intermediate transfer belt and a recording paper as an example of an output medium as a second transfer material are paired with a secondary bias transfer roll pair. The image is printed (formed) on a recording medium by transferring the image onto a recording sheet by being sandwiched between the two.

  That is, the scanning output system 103 first prints the Y, M, C, and K color print execution units 130 that are juxtaposed sequentially at a certain interval in one direction (Y, M, C, and K are attached to each; other members) The same applies to the above; when referring to them together, the colors are omitted).

  The intermediate transfer belt 136 rotates in the belt conveyance direction indicated by X in the drawing, and its overall length (peripheral length) is 949.4 mm, and the interval between the print execution units 130 is 90.48 mm. Is set.

  The print execution unit 130 transfers the toner image formed on the photosensitive drum 131, which is the first image carrier, to the intermediate transfer belt 136, which is the first transfer material and is the second image carrier. It functions as a first transfer section.

  A photosensitive drum 131 is disposed at the center of the printing execution unit 130. Around the photosensitive drum 131, a cleaner 132 that collects toner remaining without being transferred onto the photosensitive drum 131, and a photosensitive drum. A primary charger 133 that uniformly charges the surface of the photosensitive drum 131 to the same polarity as the toner; a developer 134 that visualizes the latent image formed on the photosensitive drum 131 as a toner image; and a toner output signal. And a writing scanning optical system (ROS Unit) 179 including a polygon mirror 176 and other mirrors 177a, 177b, 177c, etc. Yes.

  Further, a primary bias transfer roll (BTR) 135 is disposed at the upper portion of the print execution unit 130 for each color so as to face the photosensitive drum 131 so as to sandwich the intermediate transfer belt 136. ing.

  The primary bias transfer roll 135 is, for example, an aluminum cored bar provided with a dielectric surface layer made of a predetermined resin, and is pressed against the photosensitive drum 131. As dielectric layers, in addition to fluorine resins such as PVDF, PTFE, PFA, FEP, ETFE, PCTFE, and PVF, PMMA (polymethyl methacrylate), PP (polypropylene), PET (polyethyl terephthalate), SI (silicone resin), PBT (polybutylene terephthalate), POM (polyacetal), PC (polycarbonate), PPE (polyphenyl ether), PAR (polyarylate), PAR (polyarylate), PES (polyethersulfone), PSU (polysulfone), PPS ( Resins such as polyphenylene sulfide), PA (polyamide), PI (polyimide), PAI (polyamideimide), PEI (polyetherimide), and PEEK (polyetheretherketone) can also be employed. In particular, when PVDF is employed, the dielectric strength, dielectric constant, surface properties, etc. are excellent.

  When the primary bias transfer roll 135 is supplied with electric charges from a charge supply source (not shown), the surface potential of the primary bias transfer roll 135 is charged to a predetermined bias potential (for example, about +1 kV). Yes.

  As the structure of this charging unit, for example, a low resistance rubber layer such as carbon dispersion EPDM is provided on the outer periphery of a metal core to which a voltage on which an alternating voltage is superimposed by an external power source is applied, and carbon is used as a resistance control layer on the surface. A charging roller provided with a dispersed urethane layer or epichlorohydrin rubber layer can be used. Alternatively, a charging member such as a corona charger, a blade, or a brush can be used. In order to suppress the generation of ozone and achieve high durability, it is preferable to employ a roller charging method as in this embodiment.

  The intermediate transfer body belt 136 is laid on a plurality of belt conveyance rolls 137. For example, in the figure, idle roll (Idle Roll) 137a, drive steering roll (Drive & Steering Roll) 137b, backup roll (Back Up Roll) 137c, pre-roll (Pre Roll) 137d, and tension roll (Tension Roll) 137e. One is provided.

  A secondary bias transfer roll (2nd BTR) 138 is disposed at a position facing the backup roll 137c among the plurality of belt transport rolls 137. In the vicinity of the belt conveyance roll 137b arranged on the right side in the drawing, a belt cleaning unit 140 that collects toner remaining without being transferred onto the intermediate transfer belt 136 is arranged.

  Similar to the primary bias transfer roll 135, the secondary bias transfer roll 138 is, for example, an aluminum cored bar provided with a dielectric surface layer made of a predetermined resin, and is pressed against the photosensitive drum 131. As the dielectric layer, the same one as the primary bias transfer roll 135 can be used as the dielectric layer.

  The backup roll 137c and the secondary bias transfer roll 138 are brought into pressure contact with each other, and the toner image formed on the intermediate transfer belt 136, which is the first transfer material and the second image carrier, is transferred to the second transfer material. And a second transfer unit configured to contact and transfer to a printing paper as an output medium. When the toner image arrives at the second transfer portion as the intermediate transfer belt 136 rotates, the printing paper as the second transfer material is supplied from the standard conveying system 107 to the second transfer unit in synchronization with this, and is simultaneously illustrated. The transfer bias is applied to the secondary bias transfer roll 138 by a charge supply source (for example, a transfer high-voltage power supply), and the toner image on the intermediate transfer belt 136 side is transferred to the second transfer material (output medium / printing paper). Is done.

  Therefore, for example, similarly to the primary bias transfer roll 135, the secondary bias transfer roll 138 is supplied with charges from a charge supply source (not shown), so that the surface potential of the secondary bias transfer roll 138 has a predetermined bias. It is charged to a potential (for example, about +1 kV).

  Although details will be described later, a voltage control unit for controlling the transfer output applied to the second transfer unit is provided, and the voltage is applied over a predetermined range in the belt circumferential direction of the intermediate transfer belt 136 constituted by an endless belt. By detecting the output current value during constant voltage control by the control unit (performing current monitoring), and determining the transfer output voltage to the second transfer unit controlled by the voltage control unit based on the detected output current value, The transfer bias in the second transfer portion is controlled. As the configuration of the charging unit, the same one as the primary bias transfer roll 135 can be used.

  Although details will be described later, the presence of toner in the output medium (printing paper) as the second transfer material is utilized as a characteristic part of the present embodiment by utilizing such a current monitoring mechanism in the second transfer unit. The current monitor is executed in the non-image portion where it can be guaranteed that there is no transfer and the transfer material resistance value is detected, and the transfer voltage is determined according to the result, or the image forming conditions related to the fixing process are controlled, or predetermined When the normal range is exceeded, an abnormality handling process is performed in accordance with the fact that the second transfer material is abnormal.

  The secondary bias transfer roll 138 can also have a structure in which, for example, a conductive EPDM foam layer is provided on a metal core, and a dielectric layer of PVDF resin is provided on the surface thereof. As a result, a wide transfer nip is ensured at the transfer site, so that a conveying force can be provided, and the heat resistance of the backup roll 137c, the secondary bias transfer roll 138, and the like can be increased due to the influence of heat generated in the next fixing process. You can miss the low ones.

  The secondary bias transfer roll 138 may be one in which a dielectric layer of silicone rubber is provided on the surface of the cored bar. The silicone rubber layer is rich in elasticity, and can be elastically deformed to form a nip if it is applied to the backup roll 137c with an appropriate pressure. When the secondary bias transfer roll 138 forms a nip, the thickness of the silicone rubber layer (dielectric layer), which is a dielectric layer, changes, so that the electric capacity of the secondary bias transfer roll 138 changes, and at the nip portion. Since the surface potential of the secondary bias transfer roll 138 vibrates, the toner image can be efficiently transferred to the printing paper.

  The secondary bias transfer roll 138 can also employ a configuration in which a voltage is applied to the core metal from the outside. As an example, a DC voltage of about +1 kV is applied. In this case, a voltage obtained by superimposing an alternating voltage of Vpp (for example, about 2 kV) on a DC voltage (for example, about +2 kV) is applied to a charging roller metal core (not shown) by an external power source. Thereby, the dielectric breakdown of the dielectric layer of the secondary bias transfer roll 138 can be prevented and the transfer electric field can be strengthened, and the printing paper (output medium) as the second transfer material is good for a wide variety of types. Transfer performance can be realized.

  As another example, an AC voltage (for example, about Vpp 2 kV) may be applied to the core of the secondary bias transfer roll 138 from the outside. In this case, a DC voltage (for example, about +1 kV) is applied to a charging roller core (not shown). As a result, the AC voltage applied to the transfer roller mandrel can realize the charging uniformity of the transfer roller dielectric layer and, in addition, form a vibration transfer electric field at the transfer site, thereby efficiently secondizing the toner image. The transfer material can be transferred to a printing paper as a transfer material, and good transfer performance can be realized for a wide variety of second transfer materials (output medium, printing paper).

  Further, on the left side of the main unit 102 in the drawing, the recording paper transported downstream of the secondary bias transfer roll 138 in order to discharge the printed recording paper fed from the secondary bias transfer roll 138 to the outside of the apparatus. In addition, various conveying rolls such as a fixing roll (Fuser Roll) 139a and a fixing discharge roll (Fuser Exit Roll) 139b are provided. The fixing unit 139 is configured by the fixing roll 139a and the fixing discharge roll 139b.

  Further, on the downstream side of the fixing unit 139 of the standard discharge tray 154, a discharge roll 152 for discharging recording paper sent from the main unit 102 to the outside of the apparatus is provided.

  A patch (MOB; Mark On Belt) / Auto Density Control sensor 182 (hereinafter referred to as MOB & ADC sensor 182) prints with the tension roll 137e along the circumference of the intermediate transfer belt 136 of the printer main body 100. , A home position sensor 184 is provided between the print execution units 130Y and 130M, and an edge sensor 186 is provided between the print execution units 130M and 130C. .

  The MOB & ADC sensor 182 detects an unfixed toner image which is a reference image (toner patch / Mark On Belt) of an arbitrary density formed on the intermediate transfer belt 136 in order to obtain a stable image, and the detection result is Based on this, the density control is performed by feeding back the process conditions such as the exposure amount and the development bias, so that a constant gradation-density characteristic can be obtained even if fluctuations occur in each part of the apparatus. ing.

  The home position sensor 184 is provided to detect the reference position (home position) of the circumference of the intermediate transfer belt 136 and to maintain the rotational speed and phase of the intermediate transfer belt 136 at predetermined values based on the detection result. It has been.

  The edge sensor 186 is provided for detecting a side edge (edge) of the intermediate transfer belt 136 and controlling the lateral movement (steering) of the intermediate transfer belt 136 based on the detection result.

<Operation of basic configuration>
In the scanning output system 103 having such a configuration, first, the surface of the photosensitive drum 131 is negatively charged with the same polarity as that of the toner by the primary charger 133 and becomes a VD potential. Thereafter, a yellow (Y) laser light source (not shown) as an exposure light source is driven by a yellow toner output signal (for example, an on / off binarization signal), thereby converting the yellow toner output signal into an optical signal. The converted laser beam is irradiated toward the photosensitive drum 131Y. Thus, the laser beam scans the photosensitive drum 131Y charged by the primary charger 133Y after being cleaned by the cleaner 132Y, thereby forming an electrostatic latent image on the photosensitive drum 131Y. That is, the exposed portion on the photosensitive drum 131 that has undergone image exposure has a small absolute value of potential, and becomes a VL potential, thereby forming an electrostatic latent image.

  This electrostatic latent image is visualized as a toner image by the developing device 134Y to which yellow toner is supplied. That is, a thin layer of toner is coated on a sleeve (not shown) that is rotatably attached to the developing device 134, and this toner is negatively charged. Since the potential between the dark potential VD and the light potential VL of the photosensitive drum 131 is given to the sleeve by an external power source, the toner on the sleeve is transferred only to the portion of the light potential VL of the photosensitive drum 131 to be electrostatic. The latent image is visualized.

  Thereafter, the photosensitive drum 131Y and a primary bias transfer roll (BTR) 135Y are paired to convey the intermediate transfer belt 136, and the toner image is transferred to the intermediate transfer belt 136. The That is, in the process of nipping and conveying the intermediate transfer belt 136, the intermediate transfer belt 136 has a charge (main charge) of a polarity opposite to the charge (negative charge in this example) of the photosensitive drum 131 from the primary bias transfer roll 135. In the example, a positive charge) is applied, and the toner image on the photosensitive drum 131 is transferred and transferred to the intermediate transfer belt 136, which is the first transfer material, by electric attraction, so that the intermediate transfer belt 136 is transferred to the first transfer material. 2 functions as an image carrier. After the transfer, excess toner is removed (cleaned) from the photosensitive drum 131Y by the cleaner 132.

  Similarly, the photoreceptors charged by the primary chargers 133M, 133C, and 133K based on the corresponding M, C, and K toner output signals sequentially obtained at a predetermined interval with respect to the yellow toner output signal. By scanning the drums 131M, 131C, and 131K, electrostatic latent images are sequentially formed on the photosensitive drums 131M, 131C, and 131K.

  Each electrostatic latent image is sequentially converted into a toner image by developing units 134M, 134C, and 134K to which each color toner is supplied, and each toner image is placed on an intermediate transfer belt 136 by primary bias transfer rolls 135M, 135C, and 135K. Are sequentially transferred. After the transfer, excess toner is removed from the photosensitive drums 131M, 131C, and 131K by the cleaner 132.

  After this transfer, the portion of the intermediate transfer belt 136 to which the image has been transferred (transfer image portion) is conveyed in the direction of the secondary bias transfer roll 138. On the other hand, the standard transport system 107 transports the recording paper toward the contact portion between the belt transport roll 137c and the secondary bias transfer roll 138 by the resist roll pair 108d. Then, the transfer image portion on the intermediate transfer belt 136 and the recording sheet are conveyed to the downstream side while being sandwiched between the secondary bias transfer rolls 138, thereby printing the image on the recording sheet.

  The recording paper on which the toner images of each color of Y, M, C, and K are sequentially multiplex-transferred in this way is peeled from the intermediate transfer belt 136 and conveyed to a fixing unit 139 having a fixing roll 139a. The toner image is fixed by heat onto the recording paper by the heat fixing of the toner image by 139a, and then discharged to the outside such as the standard discharge tray 154.

<Configuration Example Focusing on Image Forming Process>
FIG. 2 is a functional block diagram of a configuration example focusing on image forming processing in the second transfer unit of the printer 1 (printer body 100) shown in FIG.

  The printer main body 100 includes a backup roll 137c and a secondary bias transfer roll 138, and a second transfer unit that contacts and transfers a toner image formed on the intermediate transfer body belt 136 to a printing sheet as a second transfer material. 210 and a print control unit 220 that controls the image forming conditions by detecting the transfer bias state in the second transfer unit 210 over a predetermined range in the belt circumferential direction of the intermediate transfer belt 136 configured as an endless belt. ing.

  The printing operation mechanism unit 340 includes a paper feed unit 342 including a manual feed tray 180 and a paper cassette 198, a printing unit 350 that executes a printing process, and a paper discharge process and punching hole formation for the processed paper. A discharge processing unit 360 that performs terminal processing such as processing and stapler processing. The control output signal CN0 of the print control unit 220 is connected to the paper feeding unit 342, the printing unit 350, and the discharge processing unit 360 of the printing operation mechanism unit 340.

  The printing unit 350 includes a conveyance unit 352 having a standard conveyance system 107 that conveys printing paper, a developing unit 354 having a developing unit 134 that develops characters and images formed as latent images on the photosensitive drum 131, and development. A transfer unit 356 as a print execution unit including a primary bias transfer roll 135 and a secondary transfer roll 138 that transfer characters and images made visible by the unit 354 to the intermediate transfer belt 136 and printing paper; And a fixing unit 358 (corresponding to the fixing unit 139 in FIG. 1) having a fixing roll 139a for fixing characters and images transferred onto the printing paper by the unit 356.

  In the drawing, the second transfer unit 210 including the backup roll 137c and the secondary bias transfer roll 138 is particularly extracted from the transfer unit 356.

  The print control unit 220 includes a transfer high voltage power source 222 that applies a high voltage to the secondary bias transfer roll 138, and a transfer bias control unit 230 that controls a transfer bias in the second transfer unit 210.

  As a transfer voltage control method, the transfer bias control unit 230 basically applies a constant current value to the secondary bias transfer roll 138 in a state where there is no transfer material in the transfer nip portion, and applies it from the generated voltage at the time of transfer. A method for determining the transfer voltage is adopted. Thus, by detecting the impedance (resistance value) of the entire transfer system when paper is not passed, even if the resistance value of the transfer roller changes, an appropriate transfer bias can be applied accordingly.

  For this reason, the transfer bias control unit 230 controls a transfer control applied to the transfer high voltage power supply 222 of the second transfer unit 210 and a transfer high voltage power supply 222 during constant voltage control by the voltage control unit 232. And an output current detection unit 234 which is an example of a transfer bias state detection unit for detecting the output current value.

  Further, the transfer bias control unit 230 has a transfer material type receiving unit 235 that receives the type of the second transfer material (output medium / printing paper) specified by the user, and the output current detected by the output current detection unit 234 has a desired value. Whether or not the detection result of the output current detection unit (transfer bias state detection unit) 234 exceeds the normal range corresponding to the transfer material type received by the transfer material type reception unit 235. The transfer output voltage for determining the transfer output voltage to the second transfer unit 210 (specifically, the transfer high voltage power supply 222) controlled by the voltage control unit 232 based on the output current value detected by the output unit 236 and the output current detection unit 234 And a determination unit 238.

  The voltage control unit 232 has a function of digitally increasing or decreasing the voltage applied to the secondary bias transfer roll 138 by controlling the transfer high voltage power supply 222.

  The output current detection unit 234 has a function of detecting current flowing from the secondary bias transfer roll 138 into the backup roll 137c. The timing for detecting the current is the same as when the paper is not passed as in the ATCV system. In order to correct the circumferential unevenness of the intermediate transfer member belt 136, the voltage generated for one turn of the intermediate transfer member belt 136 (the resulting current monitor) Value) is sampled and averaged as the current monitor range.

  The range that requires current monitoring is not limited to one round, but may be a range corresponding to the image forming range (corresponding to the output size in the circumferential direction). When a certain range in the belt 136 is set as the transfer range, only the transfer range (corresponding to the output size in the circumferential direction) may be set as the current monitor range.

  As this non-sheet-passing, for example, the front multi-rotation immediately after the power is turned on, cleaning of the surface of the photosensitive drum 131 and the intermediate transfer belt 136 performed at the time of starting up the laser printer, uniformizing the surface potential, and It is preferable to use a set-up time that is performed immediately before the printing operation or a series of device driving for the purpose of heating the fixing unit 139 or the like. By doing so, it is not necessary to provide a dedicated processing cycle for current monitoring, and the output processing time FCOT (First Copy Out Time) from when the output command is issued until the output is discharged is not affected.

  The transfer output voltage determination unit 238 uses the determination result of the determination unit 236 to determine whether or not the inflowing current has reached a desired value, so that the current flowing from the secondary bias transfer roll 138 to the backup roll 137c is constant. The value is converged to enable control equivalent to that of the ATCV type constant current circuit.

  That is, the transfer output voltage determination unit 238 receives the constant voltage output value based on the determination result CN3 of the determination unit 236 and the input calculation result from the output current detection unit 234 detected over a predetermined range in the circumferential direction of the intermediate transfer belt 136. The transfer output voltage to the second transfer unit 210 is determined based on the above. From the relationship between the current and voltage, the result is equivalent to detecting the resistance value of the second transfer unit 210 before the printing operation.

  For example, the transfer output voltage determination unit 238 refers to the determination result of the determination unit 236 and supplies control information CN1 for changing the voltage digitally to the voltage control unit 232. When the control information CN1 from the transfer output voltage determination unit 238 is input to the voltage control unit 232 in this way, the voltage control unit 232 starts an operation of digitally changing the voltage with respect to the transfer high voltage power source 222. As an example, the voltage control unit 232 converts the voltage to an analog voltage of 0 to 5 V, and further controls the output voltage of the transfer high voltage power supply 222 within a range of 0 to 5 kV.

  That is, the transfer bias controller 230 converges the current flowing from the secondary bias transfer roll 138 to the backup roll 137c to a constant value by monitoring the output current over a predetermined range in the circumferential direction of the intermediate transfer belt 136. Thus, the PTVC method for controlling the transfer bias of the second transfer unit 210 is adopted.

  Note that the current flowing through the transfer material is detected while the printing paper as the second image carrier passes through the second transfer unit 210 constituted by the backup roll 137c and the secondary bias transfer roll 138. By correcting the transfer output voltage, more accurate control can be performed. In this case, the transfer current latitude is widened by providing a certain range rather than reducing the value of the transfer current to a constant value. Limiting to a constant value has the same effect as performing constant current control. As a result, during small-size paper transfer, a large amount of transfer current flows at the portion where the secondary bias transfer roll 138 and the backup roll 137c are in contact with each other. This is to avoid a problem that becomes defective.

  The transfer current is affected by environmental fluctuations and varies depending on the resistance of the secondary bias transfer roll 138 that is the first transfer material (and the second image carrier) and the resistance of the printing paper that is the second transfer material. However, by performing current monitoring while feeding paper and applying feedback control to the transfer voltage, the control accuracy of the transfer bias is improved and printing can be performed in a stable state. As a result, it is possible to prevent image failure due to transfer failure, occurrence of plus memory, transfer failure of small size paper, excessive transfer current in a high humidity environment, and the like, and good transfer performance can be realized.

  When a transfer material whose resistance value is significantly different from the expected transfer material resistance value is used, such as when the resistance value of the transfer material is high or low, the transfer current that you want to flow during printing is the appropriate transfer current value. May deviate from range. When the impedance of the transfer material changes greatly, the transfer current becomes excessive or insufficient, and an image defect occurs. In particular, as the type of the second transfer material used for printing increases, the resistance of the second transfer material also diversifies and it is difficult to obtain a good image regardless of the environment and the type of transfer material. Become.

  On the other hand, when the second transfer material passes through the pressure nip portion between the secondary bias transfer roll 138 and the backup roll 137c of the second transfer unit 210, the second transfer material is constant after the second transfer material is inserted. If the output voltage of the transfer high-voltage power supply 222 is corrected according to the current detection result of the output current detection unit 234 after the time, the voltage correction value is used as the resistance detection result of the second transfer unit 210 before the printing operation. By changing according to the current detection result, it becomes possible to obtain a good image regardless of the resistance value of the second transfer material, that is, the second transfer material having any resistance value.

  The determination unit 236 included in the transfer bias control unit 230 determines whether the difference between the output current values at a plurality of positions on the intermediate transfer belt 136 detected by the output current detection unit 234 exceeds a predetermined normal range. To do.

  Further, the print control unit 220 responds that a characteristic abnormality has occurred in the intermediate transfer belt 136 as the first transfer material on the condition that the determination unit 236 determines that the predetermined normal range is exceeded. An abnormality handling processing unit 260 that performs processing is provided.

  The output current detection unit 234 is not limited to the non-sheet-passing state or the above-described sheet passing as a function unique to the present embodiment, but the output medium (printing paper) that is the second transfer material is the second transfer unit 210. The transfer bias state in the second transfer unit 210 in a predetermined period after the contact nip portion between the backup roll 137c and the secondary bias transfer roll 138 is reached is detected. In particular, in the secondary transfer with respect to the output medium, the current monitor of the non-image portion in the second transfer material (output medium) is sampled to detect the resistance value of the second transfer material (output medium). The reason why the current monitoring is performed in the non-image portion is to prevent the influence of the toner from being affected by the current detection for the paper quality determination.

  Current monitoring of the non-image portion of the second transfer material (output medium) can be realized by using, for example, non-image data or by stopping the operation of the writing scanning optical system 179 and performing trial printing. Good. Alternatively, the current monitoring may be performed at the front end portion that can guarantee the absence of toner by the edge erase function in the secondary transfer to the paper.

  The determination unit 236 determines a current value (resulting resistance value) caused by the thickness and material of the output medium from the current monitor result of the non-image portion, and notifies the abnormality response processing unit 260 of the determination result.

  The abnormality handling processing unit 260 of the present embodiment includes a storage unit 262 that stores a history that the output medium that is the second transfer material is abnormal, and an output medium that is the second transfer material is abnormal. A notification unit 264 that notifies information to a user, a management center, and the like, and a stop control unit 266 that stops the image forming process.

  Although the current value detected by the output current detection unit 234 can always be stored in the storage unit 262, in this case, the amount of information becomes enormous. In order to reduce the storage capacity of the storage unit 262, it is preferable to leave only the minimum necessary information. Here, for practical purposes, it may be considered sufficient that an abnormality occurs to be left as the current history.

  For this reason, on the condition that the abnormality handling processing unit 260 determines that the determination unit 236 exceeds the predetermined normal range, the output current detection unit 234 is in response to the output medium being the second transfer material being abnormal. The process of leaving the current value detected by is stored in the storage unit 262 is performed.

  FIG. 3 is a diagram illustrating an example of a current monitor value detected by the output current detection unit 234. 4 and 5 are diagrams for explaining an example of the relationship between the paper quality and the current monitor output range and the paper quality determination criteria (paper quality determination logic). Here, an example of current monitoring at the front end portion that can ensure that there is no toner, which is the target portion of the present embodiment, is shown.

  The output current detection unit 234 is configured to measure a current value between the backup roll 137c and the secondary bias transfer roll 138. Specifically, in the state where a predetermined voltage (high voltage for transfer) is output to the secondary bias transfer roll 138 by the transfer high voltage power supply 222 and the voltage control unit 232, the intermediate transfer body belt 136 is rotated in the belt rotation direction. The output current value is detected / calculated at a plurality of positions in the cycle at a predetermined sampling cycle, and the current monitor value, which is the detection / calculation result for one rotation of the belt, is stored in a storage unit (not shown) at a predetermined timing. The transfer output voltage determination unit 238 is notified.

  The determination unit 236 determines that a characteristic abnormality has occurred in the secondary bias transfer roll 138 when the current monitor value at each sample point sampled by the output current detection unit 234 deviates from the predetermined normal range. to decide.

  Here, the current monitor value pulsates, and the average value thereof is affected by the setting by the transfer output voltage determination unit 238. Therefore, the change of the current monitor value is more preferable than the determination based on the magnitude of the current monitor value at each sample point. The degree should be a criterion.

  For example, when the difference Δ1 between the current monitor values at the respective sample points sampled by the output current detection unit 234 exceeds the preset threshold Th1, the determination unit 236 causes a characteristic abnormality in the secondary bias transfer roll 138. Is determined to have occurred.

  When the determination unit 236 detects a characteristic abnormality of the secondary bias transfer roll 138, the abnormality handling processing unit 260 performs control according to the setting at the time of abnormality detection. It is preferable that the user can select and decide what kind of control is performed. Further, it is more preferable that a plurality of controls can be arbitrarily combined and selected and determined.

  Further, as a process unique to the present embodiment, as shown in FIG. 3, the determination unit 236 detects the current detection result detected by the output current detection unit 234 using the edge-erasing function as a current monitoring period for the tip portion where no toner exists. The image forming conditions related to the fixing process are controlled based on the above. Further, the determination unit 236 determines whether or not the current detection result during the current monitoring period at the front end exceeds the normal range corresponding to the transfer material type (paper quality) received by the transfer material type reception unit 235, thereby determining abnormality. Sometimes, the result of the determination is notified to the abnormality handling processing unit 260.

  In other words, the determination unit 236 calculates the resistance value of the output medium based on the current value measured by the output current detection unit 234 at the front end where no toner is present, and automatically based on the calculated resistance value. The image forming conditions related to the fixing process are controlled, it is determined whether the paper quality designated by the user is correct, and if it is abnormal, the determination result (abnormality notification) CN3 is notified to the abnormality handling processing unit 260. Specifically, when the difference between the detected resistance value of the paper and the resistance value corresponding to the paper quality designated by the user is outside the specified range, it is detected as a paper quality mismatch.

  When automatically controlling image forming conditions related to the fixing process, for example, trial printing is performed by using non-image data or by stopping the operation of the writing system, and from the current monitor result in this trial printing, the output medium The current value (resulting resistance value) that appears as a different result depends on the thickness and material of the toner, and the fixing temperature and transport speed (corresponding to the fixing processing time) in the fixing unit 139 are changed according to the determination result. In this way, the control signal CN2 is sent to the printing operation mechanism unit 340 to control it. By doing this, even if there is a mistake in setting the paper type, the setting can be changed to an appropriate image forming condition according to the paper type detected by the output current detection unit 234, and an appropriate image forming process can be executed.

  For example, in the example shown in FIG. 4 and FIG. 5, each figure (A) shows a range of current values (unit: mA) that each paper quality can take for four types of paper quality. Here, in the examples shown in FIGS. 4 and 5, the image forming conditions related to the fixing process are low temperature processing and high-speed conveyance because plain paper has low thermal resistance, but plain paper → thick paper 1 → thick paper 2 → Thermal resistance increases in the order of OHP, so high-temperature processing and low-speed conveyance are required.

  Therefore, when the fixing temperature and the conveyance speed (corresponding to the fixing processing time) in the fixing unit 139 are automatically changed based on the current monitor result, the automatic setting shown in each figure (B) is made with emphasis on the fixing performance. As in the paper quality determination logic, the paper quality side with the higher thermal resistance is preferentially selected and set.

  In the first example shown in FIG. 4, the current range that each paper quality can take is the same value for the maximum value on the low heat resistance side and the minimum value on the next high heat resistance side, and the overlap portion is the critical point. Therefore, by setting the minimum value of each paper quality to “more than” of the determination logic and setting the maximum value of each paper quality to “less than” of the determination logic, the paper quality can be separated relatively clearly.

  On the other hand, in the second example shown in FIG. 5, the current range that each paper quality can take is different from the maximum value on the low thermal resistance side and the minimum value on the next high thermal resistance side, and there is a considerable overlap portion. . For this wide overlap portion, it is not possible to specify which paper quality is based on the current monitor result alone. Therefore, in this case, in order to preferentially select and set the paper quality side with the larger thermal resistance, the minimum paper quality value on the low thermal resistance side is set to “above” of the judgment logic, and the minimum paper quality on the next high thermal resistance side is set. By setting the value to “less than” in the judgment logic, the paper quality is separated. By doing so, it is possible to reliably prevent the fixing process by the low-temperature / high-speed conveyance from being performed on the paper quality that needs the fixing process at the high-temperature / low-speed conveyance.

  Further, the determination unit 236 determines whether or not the paper quality mismatch, and the abnormality handling processing unit 260 notified of the abnormality determination result CN3 indicates that the paper quality designated by the user is inappropriate (that is, the second transfer). When the material is abnormal and a paper quality mismatch is detected, an abnormality handling process is performed.

  For example, the determination unit 236 detects the current monitor detected within the range of current values that can be taken by the paper quality specified by the user, such as the paper quality determination logic for abnormality determination shown in FIGS. 4C and 5C. Whether or not there is a paper quality mismatch may be determined based on whether or not a value exists.

  The abnormality handling processing unit 260 performs adaptive processing according to the occurrence of a paper quality mismatch. For example, as setting example 1, the history of detecting that the second transfer material is abnormal, history of job execution, job type (print, copy, etc.), job file name (print file), etc. Are stored in the storage unit 262 in association with identifiable information.

  The history that the second transfer material stored in the storage unit 262 is abnormal includes not only that the second transfer material is different from the user's designation, but also that the output current detection unit 234 has the meaning of leaving the evidence. It is preferable to store information on the detected output current value.

  By doing so, it is possible to recognize a mismatch between the paper quality designated by the user and the detected paper quality, accurately store the history in the storage unit 262 inside the machine, and confirm it by a predetermined procedure. When the paper quality detection information is detected and the history is left inside the machine, it is determined how many days and months the job was processed, and after confirming whether a paper quality mismatch was detected when an image print failure occurred. Thus, it is possible to explain to the user whether the cause of the failure is due to a user operation error (paper quality designation error) or a machine failure.

  Further, as setting example 2, when the abnormality handling processing unit 260 detects that the second transfer material is abnormal, the abnormality handling processing unit 260 uses the notification unit 264 to display a user interface using a multimedia device such as a display device or an audio device. To the user and wait for processing instructions. The user instructs the re-output by changing the operation condition as necessary by the notification via the notification unit 264.

  When a paper quality mismatch is detected and notified to the user, the user can be inquired whether to execute the process as it is. Since re-output under different operating conditions and re-output after failure repair can be executed, it is possible to avoid image quality problems and fixing unit failures.

  In addition, when a non-standard size using the manual feed tray 180 is used, only one sheet is first flowed, and when there is a paper quality defect (difference from user designation), the user can be inquired whether or not to execute it as it is.

  Furthermore, if notification is made that the background image of the next job can be printed, the user can avoid leakage of important information by setting the paper quality setting to a normal state.

  Further, as setting example 3, when the stop control unit 266 of the abnormality handling processing unit 260 detects that the second transfer material is abnormal, the stop processing unit 266 stops the image forming process (printing process) as a paper quality mismatch (Fail). As described above, the control signal CN4 is sent to the printing operation mechanism unit 340 for control. In this way, defective printing can be prevented by stopping printing when a paper quality mismatch is detected.

  When the image forming process (printing process) is stopped, the leading end of the sheet is not immediately moved to the fixing unit 139 and is stopped immediately (so-called paper jammed state). Here, since the distance between the second transfer unit 220 and the fixing unit 139 is short, only the front end portion can be transferred and stopped in an unfixed state. Although there may be header information, there is almost no normal character information or image information, and since it may be considered that there is almost no printing, the problem of smearing hardly occurs. The toner remaining on the intermediate transfer belt 136 without being transferred is removed by the belt cleaning unit 140.

  In this setting example 3, in combination with the setting example 2 described above, when a paper quality mismatch is detected, the user is notified via the notification unit 264 and printing is stopped via the stop control unit 266. It is effective.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which such changes or improvements are added are also included in the technical scope of the present invention.

  Further, the above embodiments do not limit the invention according to the claims (claims), and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. Absent. The embodiments described above include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.

  For example, in the above embodiment, a plurality of engines corresponding to each output color are arranged in-line, and a color image is formed by processing images of each output color in parallel (simultaneously) with each engine. The example applied to the tandem type color image forming apparatus configured as described above has been described. However, as long as the intermediate transfer type is provided with the intermediate transfer belt, the operation and effect of the print control unit 220 described in the above embodiment is achieved. The application range is not limited to the configuration of the above embodiment.

  For example, an image of each color is sequentially formed on an image carrier such as a photosensitive drum by a single engine (photosensitive unit), and this is overlaid and transferred to an intermediate transfer member (primary transfer material) one color at a time. The present invention can also be applied to a multi-pass type (cycle type) color image forming apparatus that forms a color image.

  Further, although the intermediate transfer system having the intermediate transfer mechanism has been described, the invention is not limited to the intermediate transfer system.

1 is a diagram illustrating a configuration example when an image forming apparatus according to the present invention is applied to a printer. FIG. 3 is a functional block diagram of a configuration example focusing on image forming processing in a second transfer unit of the printer illustrated in FIG. 1. It is a figure which shows an example of the current monitor value detected by the output current detection part. It is a figure explaining the 1st example of the relationship between paper quality and an electric current monitor output range, and paper quality criteria. It is a figure explaining the 2nd example of the relationship between paper quality and an electric current monitor output range, and paper quality criteria.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer, 100 ... Printer main body, 102 ... Main unit, 103 ... Scanning output system, 105 ... Cartridge part, 107 ... Standard conveyance system, 108 ... Roll member, 130 ... Print execution part, 131 ... Photoconductor drum, 132 ... Cleaner, 133 ... primary charger, 134 ... developing device, 135 ... primary bias transfer roll, 136 ... intermediate transfer belt, 137c ... backup roll, 138 ... secondary bias transfer roll, 139 ... fixing unit, 139a ... fixing Roll, 139b ... Fixing discharge roll, 140 ... Belt cleaning unit, 179 ... Writing scanning optical system, 180 ... Manual tray, 182 ... MOB & ADC sensor, 184 ... Home position sensor, 186 ... Edge sensor, 190 ... Feed tray ... second transfer unit, 220 ... print control unit, 222 ... transfer high power Power supply unit 230 ... Transfer bias control unit 232 ... Voltage control unit 234 ... Output current detection unit 235 ... Transfer material type reception unit 236 ... Judgment unit 238 ... Transfer output voltage determination unit 260 ... Abnormality response processing unit 262 ... Storage unit, 264 ... Notification unit, 266 ... Stop control unit, 340 ... Printing operation mechanism unit

Claims (11)

An image forming apparatus that forms an image on an output medium that is a transfer material by forming a latent image on an image carrier and transferring the image obtained by developing the latent image onto the transfer material. And
A transfer unit that contacts and transfers the image formed on the image carrier to the transfer material;
A fixing unit for fixing an image formed on the transfer material;
A transfer bias state detection unit for detecting a transfer bias state in the transfer unit in a predetermined period after the transfer material reaches the transfer unit;
An image forming apparatus comprising: a control unit that controls image forming conditions related to a fixing process based on a detection result of the transfer bias state detection unit. The image forming apparatus according to claim 1, wherein the control unit includes a transfer bias control unit that controls a transfer bias in the transfer unit. An image forming apparatus that forms an image on an output medium that is a transfer material by forming a latent image on an image carrier and transferring the image obtained by developing the latent image onto the transfer material. And
A transfer unit that contacts and transfers the image formed on the image carrier to the transfer material;
A transfer bias state detection unit that detects a transfer bias state in the transfer unit in a predetermined period after the transfer material reaches the transfer unit;
A determination unit that determines whether the detection result of the transfer bias state detection unit exceeds a predetermined normal range;
An image forming apparatus comprising: an abnormality handling processing unit that performs a process in response to an abnormality of the transfer material on the condition that the determination unit determines that the predetermined normal range is exceeded. A transfer material type receiving unit that receives the type of the transfer material specified by the user;
The determination unit determines whether the detection result of the transfer bias state detection unit exceeds the predetermined normal range corresponding to the type of the transfer material received by the transfer material type reception unit. The image forming apparatus according to claim 3. The image forming apparatus according to claim 3, wherein the abnormality handling processing unit includes a storage unit that stores a history that the transfer material is abnormal. The image forming apparatus according to claim 3, wherein the abnormality handling processing unit includes a notification unit that notifies information that the transfer material is abnormal. The image forming apparatus according to claim 3, wherein the abnormality handling processing unit includes a stop control unit that stops the image forming process. The image according to any one of claims 1 to 7, wherein the transfer bias state detection unit detects the transfer bias state in an image-free portion where no image is formed on the transfer material. Forming equipment. Forming a latent image on the first image carrier and developing the image obtained by developing the latent image onto a first transfer material; and a first transfer material comprising: A second transfer unit that transfers the image transferred onto the second image carrier as a second image carrier to a second transfer material;
The transfer bias state detection unit detects a transfer bias state in the second transfer unit during a predetermined period after the second transfer material reaches the second transfer unit. 9. The image forming apparatus according to any one of items 1 to 8. In this image forming method, a latent image is formed on an image carrier, and an image obtained by developing the latent image is transferred onto a transfer material to form an image on an output medium as the transfer material. And
After the image formed on the image carrier is contact-transferred to the transfer material at the transfer unit, the transfer material is transferred to the transfer unit when the image formed on the transfer material is fixed at the fixing unit. An image forming method, comprising: detecting a transfer bias state in the transfer portion in a predetermined period after the arrival, and controlling an image forming condition related to a fixing process based on the detection result. In this image forming method, a latent image is formed on an image carrier, and an image obtained by developing the latent image is transferred onto a transfer material to form an image on an output medium as the transfer material. And
When the image formed on the image bearing member is contact-transferred to the transfer material at the transfer portion, the transfer bias state in the transfer portion in a predetermined period after the transfer material reaches the transfer portion is detected, An image forming method comprising: performing an abnormality handling process in response to an abnormality of the transfer material when exceeding a predetermined normal range.

Images