JP2009003304A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of enhancing relative positional precision between a transfer device and a fixing device, without increasing a cost, and free from risks of generating a curl, a wrinkle or the like in a transfer material and of generating a color shift in a toner image. <P>SOLUTION: The toner image on an intermediate transfer belt 10 (image carrier) is transferred to the transfer material P such as a paper sheet by a secondary transfer device 60, and the transfer material is passed thereafter through the fixing device 40 to fix unfixed toner T on the transfer material onto the transfer material by the fixing device. In this image forming apparatus of such constitution, the secondary transfer device is provided movably to be turned between an operation position A for transfer and an evacuation position B evacuated from the position, or to be moved likely, and the secondary transfer device is formed with an abutting part 65, to hold it in the operation position by abutting to a positioning protrusion 66 of the fixing device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a plotter, a facsimile, or a complex machine thereof. Among them, in particular, charging, writing, and development are performed to form a toner image on the photosensitive member, and the toner image is transferred directly or indirectly via the intermediate transfer member by the transfer device, and the transferred toner image is fixed to the fixing device. The present invention relates to an electrophotographic image forming apparatus that fixes an image and records an image on a transfer material such as paper.

  Image forming apparatuses such as printers, facsimiles, and copiers record images including characters, symbols, and the like on transfer materials such as paper, cloth, and OHP films based on image information. There are various types of such image forming apparatuses. Among them, the electrophotographic image forming apparatus can record high-definition images on plain paper at a high speed. Widely used.

  In an electrophotographic image forming apparatus, a charging device, a writing device, a developing device, a transfer device, a cleaning device, a static eliminator, and the like are arranged around a drum-shaped or belt-shaped photoconductor. After being uniformly charged, writing is performed to form an electrostatic latent image on the surface of the photoreceptor, and by attaching toner, the electrostatic latent image is developed to form a toner image on the photoreceptor, The toner image is transferred directly or indirectly via an intermediate transfer member such as a belt, and the image is recorded on the transfer material.

  The transfer material after the toner image is transferred is guided to a fixing device, and unfixed toner is fixed on the transfer material. On the other hand, the surface of the photoconductor after image transfer is cleaned by a cleaning device and discharged by a charge removing device to prepare for image formation again.

  By the way, in this type of electrophotographic image forming apparatus, the relative position of the transfer device and the fixing device is determined such as the conveyance quality such as the presence or absence of occurrence of curling or wrinkling of the transfer material, and the color overlay accuracy of the toner image. This is very important because it greatly affects the image quality. Therefore, conventionally, the transfer device and the fixing device are each supported by a casing provided in the main body of the image forming apparatus so that the mounting accuracy of each other is ensured on the basis of the casing, and the parallelism is adjusted in the manufacturing process. Or tightening the dimensional accuracy of each.

JP-A-6-183627 Japanese Patent No. 3454290

  However, even if the parallelism is strict, there are problems such as curling and wrinkling of the transfer material and color deviation of the toner image depending on various usage conditions of the user. In recent years, as the cost of image forming apparatuses has further increased, adjusting the parallelism of each other in the manufacturing process and increasing the dimensional accuracy of each of the image forming apparatuses has been a factor in increasing costs.

  Accordingly, a first object of the present invention is to increase the relative positional accuracy of the transfer device and the fixing device without causing an increase in cost, and the transfer material may be curled or wrinkled, or the toner image may be color-shifted. It is an object of the present invention to provide an image forming apparatus that does not have the risk of being damaged.

  A second object of the present invention is to improve the conveyance stability of the transfer material after the toner image is transferred from the transfer device to the fixing device.

  A third object of the present invention is to accurately guide the transfer material after transferring the toner image from the transfer device to the fixing device in accordance with various conditions.

  A fourth object of the present invention is to facilitate fine adjustment of the transfer outlet guide member and the fixing inlet guide member.

  A fifth object of the present invention is to accurately guide the transfer material after transferring the toner image from the transfer device to the fixing device in accordance with the sheet passing conditions.

  A sixth object of the present invention is to accurately guide the transfer material after transferring the toner image from the transfer device to the fixing device in accordance with the type of the transfer material.

  A seventh object of the present invention is to accurately guide a transfer material after transfer of a toner image from a transfer device to a fixing device in accordance with installation environment conditions.

  An eighth object of the present invention is to accurately guide the transfer material after transferring the toner image from the transfer device to the fixing device in accordance with the image conditions of the transfer material.

For this reason, the invention described in claim 1 is to achieve the first object described above.
After a toner image on an image carrier such as a photosensitive member or an intermediate transfer member is transferred to a transfer material such as paper by a transfer device, the transfer material is passed through a fixing device and unfixed toner on the transfer material by the fixing device. In an image forming apparatus in which is fixed to a transfer material,
The abutting portion is provided so as to be movable by rotating the transfer device to an operating position for performing transfer and a retracted position retracted from the position, and is held at the operating position by abutting against the fixing device Is formed in the transfer device.

  Then, at the time of assembly, the transfer device is held in the operating position by moving the transfer device, for example, by rotating the abutting portion against the fixing device. In use, after the toner image on the image carrier is transferred to the transfer material by the transfer device, the transfer material is passed through the fixing device, and the unfixed toner on the transfer material is fixed to the transfer material by the fixing device.

  According to a second aspect of the present invention, in order to achieve the second object described above, in the image forming apparatus according to the first aspect, a transfer outlet guide member that guides a transfer material after image transfer from the transfer device. And a fixing inlet guide member for guiding the transfer material after image transfer when it is received by the fixing device. Then, the transfer material after the image transfer is guided by the transfer outlet guide member and sent out from the transfer device, and is guided by the fixing inlet guide member and received by the fixing device.

  According to a third aspect of the present invention, in order to achieve the third object described above, in the image forming apparatus according to the second aspect, both the transfer outlet guide member and the fixing inlet guide member are provided so that their positions can be adjusted. It is characterized by being. Then, both the transfer outlet guide member and the fixing inlet guide member are adjusted to the optimum positions where the transfer material after image transfer can be accurately guided.

  According to a fourth aspect of the present invention, in order to achieve the fourth object described above, in the image forming apparatus according to the third aspect, the transfer outlet guide member and the fixing inlet guide member are provided in conjunction with each other. It is characterized by being. When the transfer outlet guide member and the fixing inlet guide member are moved and adjusted, they interlock with each other.

  According to a fifth aspect of the present invention, in order to achieve the fifth object described above, in the image forming apparatus according to the third or fourth aspect, the transfer outlet guide member, the fixing inlet guide member, Is provided so that the position thereof can be freely adjusted. Then, the position of the transfer outlet guide member and the fixing inlet guide member are adjusted according to whether the single-sided or double-sided sheet is passed, or the sheet passing conditions such as the transfer speed of the transfer material.

  According to a sixth aspect of the invention, in order to achieve the sixth object described above, in the image forming apparatus according to the third or fourth aspect, the transfer outlet guide member and the fixing inlet guide member according to the type of transfer material. Are provided so as to be freely adjustable in position. And depending on the type of transfer material (paper, resin sheet, coated paper, label paper, envelope, backing paper, recycled paper, etc.), thickness, waist strength (rigidity), electrical resistance, roughness, etc. The positions of the transfer outlet guide member and the fixing inlet guide member are adjusted.

  According to a seventh aspect of the present invention, in order to achieve the seventh object described above, in the image forming apparatus according to the third or fourth aspect, the transfer outlet guide member, the fixing inlet guide member, Is provided so that the position thereof can be freely adjusted. Then, the position of the transfer outlet guide member and the fixing inlet guide member is adjusted according to the installation environment such as ambient temperature and humidity.

  According to an eighth aspect of the present invention, in order to achieve the eighth object described above, in the image forming apparatus according to the third or fourth aspect, the transfer outlet guide member and the fixing inlet guide according to the image condition of the transfer material. The member is provided such that the position thereof can be freely adjusted. Then, the position of the transfer outlet guide member and the fixing inlet guide member is adjusted according to the image conditions of the transfer material such as the image area, the photographic image quality, and the charge amount.

  According to the first aspect of the present invention, since the transfer device is held at the operating position by moving the transfer device and abutting the abutting portion against the fixing device, the housing provided in the image forming apparatus main body is provided. It is possible to eliminate the accumulation of tolerances without intervening, and to directly position the transfer device and the fixing device to ensure parallelism. Therefore, without increasing the cost, the relative position accuracy between the transfer device and the fixing device is improved, and an image forming apparatus that does not cause curling or wrinkles in the transfer material or color misregistration in the toner image is provided. can do.

  According to the second aspect of the present invention, the transfer material after the image transfer is guided by the transfer outlet guide member and fed from the transfer device, and is guided by the fixing inlet guide member and received by the fixing device. The transfer material after the toner image is transferred from the transfer device to the fixing device by increasing the relative positional accuracy of the guide members and facilitating the setting of the steps and gaps between the guide members between the transfer device and the fixing device. In addition, it is possible to improve the conveyance stability of the image, and to eliminate and reduce wrinkles and ear folds of the transfer material caused by poor entry into the fixing device and image dust caused by a step between the guide members.

  According to the third aspect of the present invention, the transfer outlet guide member and the fixing inlet guide member are adjusted to the optimum positions where the transfer material after the image transfer can be accurately guided. The material is accurately guided from the transfer device to the fixing device according to various conditions, eliminating wrinkles and ear folds caused by improper entry to the fixing device and image dust caused by steps between the guide members. And can be reduced.

  According to the fourth aspect of the present invention, when the transfer outlet guide member and the fixing inlet guide member are moved and adjusted, they are interlocked with each other, so that both guide members can be easily finely adjusted.

  According to the fifth aspect of the present invention, since both guide members are adjusted in position according to the sheet passing condition, the conveyance stability of the transfer material after the transfer of the toner image is improved, and this occurs due to poor entry into the fixing device. Problems due to the curling of the transfer material, rubbing against the guide member, dust image and the like can be eliminated and reduced.

  According to the sixth aspect of the present invention, the position of the transfer outlet guide member and the fixing inlet guide member are adjusted according to the type of transfer material, thickness, waist strength, electrical resistance, roughness, and the like. Therefore, it is possible to improve the conveyance stability of the transfer material after the toner image is transferred, and to eliminate or reduce the problems caused by the poor entry into the fixing device.

  According to the seventh aspect of the invention, since the position of the transfer outlet guide member and the fixing inlet guide member is adjusted according to the installation environment, the conveyance stability of the transfer material after the toner image transfer is improved, and the fixing is performed. Problems caused by poor entry into the apparatus can be eliminated and reduced.

  According to the eighth aspect of the present invention, the position of the transfer outlet guide member and the fixing inlet guide member is adjusted according to the image condition of the transfer material such as the image area, the photographic image quality, and the difference in charge amount. It is possible to improve the conveyance stability of the transfer material after image transfer, and to eliminate or reduce problems caused by poor entry into the fixing device.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 shows an overall schematic configuration of an internal mechanism of a tandem type color printer which is an example of an electrophotographic image forming apparatus.

  An image forming unit 400 is installed in the printer main body 100. As shown in FIG. 2, the image forming unit 400 includes four image forming units 500 of yellow (Y), cyan (C), magenta (M), and black (K), and an intermediate transfer unit 600. Yes. Both units 500 and 600 are detachably provided. In the intermediate transfer unit 600, an endless intermediate transfer belt 10 as an intermediate transfer member, which is an image carrier, is wound around three rollers 12 to 14, and a belt cleaning device 15 is disposed on the left side in the drawing. .

The four image forming units 500K, 500M, 500Y, and 500C have the same configuration except that the colors of toner to be used are different, and are arranged in tandem along the intermediate transfer belt 10 below the intermediate transfer unit 600. .
FIG. 3 shows a schematic configuration of one image forming unit 500.

  Each image forming unit 500 includes a drum-shaped photoconductor 20. Around the photoconductor 20, there are a charging device 21 made of a charging roller, a developing device 22, a primary transfer device 16 made of a transfer roller across the intermediate transfer belt 10, a charge removing device 23 made of a discharge lamp, a cleaning device 24, and the like. Has been placed.

  Here, the charging device 21 uniformly charges the surface of the photoconductor 20 by applying a voltage in contact with the photoconductor 20. In the illustrated example, a contact charging method using a charging roller as the charging device 21 is used. However, a brush charging method, a scorotron charging method, or the like may be used. The developing device 22 includes a stirring unit and a developing unit, and the developer that has not been used for development is returned to the stirring unit and reused. The toner concentration in the stirring unit is detected by a toner concentration sensor, and is controlled so that the concentration becomes constant.

  Further, the primary transfer device 16 adopts a transfer roller system, and as shown by reference numerals 16Y, 16C, 16M, and 16K in FIG. 2, the intermediate transfer belt 10 is sandwiched between the photoreceptors 20Y, 20C, 20M, and 20K, respectively. It is arranged to press. As the primary transfer device 16, a conductive brush shape, a non-contact corona charger, or the like can also be employed.

  As shown in FIG. 1, the writing device 26 is disposed under the image forming unit 400. The writing device 26 is, for example, for forming an electrostatic latent image on the photoconductor 20 provided in each image forming unit 500 based on image information of a document read by a scanner.

  Then, as the photoconductor 20 rotates clockwise in FIG. 3, the surface of the photoconductor 20 is uniformly charged by the charging device 21. Next, writing light is irradiated by the writing device 26 based on the image signal, and an electrostatic latent image is formed on the photoconductor 20. Thereafter, the toner is attached to the photoreceptor 20 by the developing sleeve 27 of the developing device 22, and the attached toner is primarily transferred onto the intermediate transfer belt 10 at the primary transfer position N1 by the primary transfer device 16.

  At this time, the toner remaining on the photoconductor 20 without being transferred is initialized by removing the surface potential by the neutralizing device 23 and then scraped off by the cleaning member 28 such as a cleaning blade of the drum cleaning device 24 to be removed. Then, it is prepared for image formation again. The toner recovered by the drum cleaning device 24 is recovered by the developing device 22 by a recovery screw (not shown) or a toner recycling device and can be reused.

  As shown in FIG. 1, below the writing device 26, paper feed trays 30 are provided in multiple stages (in the illustrated example, in two stages). Correspondingly, each paper feed tray 30 is provided with a paper feed means 31 for feeding the transfer material P stored therein one by one, and a transport path 32 for transporting the transfer material P fed by the paper feed means 31. Is formed. The conveyance path 32 from each paper feed tray 30 joins and extends upward, and continues to the paper discharge stack unit 33 on the printer main body 100.

  A secondary transfer roller 34 of the secondary transfer device 60 is disposed in the transport path 32 so as to face the intermediate transfer unit 600, and a secondary transfer position N2 is formed. A registration roller pair 36 is provided upstream of the secondary transfer position N2. A fixing device 40 is disposed downstream of the secondary transfer position N2, and a paper discharge roller pair 38 is further provided downstream thereof. In addition to the transfer roller, the secondary transfer roller 34 can also be configured using a transfer belt, a transfer charger, or the like.

  As the intermediate transfer belt 10 rotates counterclockwise in the figure, the yellow, cyan, magenta, and black toner images formed on the photoreceptor 20 of each image forming unit 500 are moved to the primary transfer position N1 as described above. The images are sequentially transferred and overlaid, and a color image is formed on the intermediate transfer belt 10. On the other hand, the transfer material P fed out by the paper feeding means 31 is sent to the secondary transfer position N2 through the transport path 32 with timing by the registration roller pair 36.

  The color image on the intermediate transfer belt 10 is secondarily transferred by the secondary transfer roller 34 to the transfer material P sent to the secondary transfer position N2. Thereafter, the transfer material P is conveyed to the fixing device 40 where the toner image is fixed and discharged onto the paper discharge stack 33 by the paper discharge roller pair 38. At this time, the toner remaining on the intermediate transfer belt 10 without being transferred is scraped off and removed by a cleaning member such as a cleaning blade of the belt cleaning device 15.

  By the way, although not shown in the figure, the printer main body 100 is provided with toner bottles that can accommodate toners to be supplied to the image forming units 500Y, 500C, 500M, and 500K. Reference numeral 19 denotes a manual paper feed tray.

FIG. 4 shows a schematic configuration of the fixing device 40 provided in the color printer of FIG.
The fixing device 40 is detachably provided in the printer main body 100. The fixing device 40 is provided with a rectangular parallelepiped casing 41. On the upper and lower surfaces of the casing 41, a transfer material P introduction port 42 and a discharge port 43 that are elongated in the length direction are formed to face each other.

  In the casing 41, a fixing roller 44 made of an elastic body such as rubber is rotatably supported around a shaft 45 on one side of a transfer material conveyance path connecting the introduction port 42 and the discharge port 43. . The driving force of the driving motor M is transmitted to the shaft 45 of the fixing roller 44 so as to rotate counterclockwise. In addition, a heating roller 46 that is a hollow metal roller is supported in the casing 41 so as to rotate about a shaft 47 so as to be separated from the fixing roller 44, and a halogen heater and other heaters 48 are provided inside. One or more books are stored.

  A heat-resistant endless fixing belt 50 is wound around the fixing roller 44 and the heating roller 46, and a tension roller 52 urged by a spring 51 is pressed from the inside. In this example, the heater 48 is disposed inside the heating roller 46, but may be disposed outside the fixing belt 50. In addition to the heater, a heat generating layer may be provided on the peripheral surface of the fixing belt 50 and an electromagnetic induction coil may be disposed around the heat generating layer.

  On the other hand, in the casing 41, a pressure roller 54 is supported on the other side of the transfer material conveyance path so as to be rotatable about a shaft 53. The pressure roller 54 is pressed against the fixing roller 44 via the fixing belt 50 to be transferred. A fixing nip N is formed at the conveyance path position. The pressure roller 54 is a hollow roller, in which a heater 55 is housed, a cleaning roller 56 is pressed against the peripheral surface, and is configured to be displaced relative to the fixing roller 44. The cleaning roller 56 removes paper dust and toner adhering to the surface of the pressure roller 54, but is not necessarily essential.

  A plate-shaped fixing inlet guide member 57 is supported under the pressure roller 54 so as to form a transfer material conveyance path inside the casing 41 in the vicinity of the inlet 42, and on the pressure roller 54. Is fixed so as to form a transfer material conveyance path inside the casing 41 in the vicinity of the discharge port 43, and a plate-like fixing outlet guide member 58 is supported. A separation member 59 is supported at a position facing the fixing outlet guide member 58 across the transfer material conveyance path. The separating member 59 is a plate-like or comb-like member extending in the axial direction of the fixing roller 44 and is provided in a state separated from the surface of the fixing belt 50.

FIG. 5 shows the configuration of the secondary transfer device 60 together with the fixing device 40 of FIG.
In the secondary transfer device 60, a secondary transfer roller 34 is rotatably provided in a casing 61, and a plate-shaped transfer inlet guide member 62 and a transfer outlet guide member 63 are both fixedly provided so that a support shaft 64 is centered. As shown in the figure, the actuator is movably provided at an operating position A indicated by a solid line and a retracted position B indicated by a chain line. An abutting portion 65 is formed on the casing 61, and the secondary transfer device 60 is operated by abutting the abutting portion 65 against a positioning projection 66 (not shown in FIG. 4) of the fixing device 40. The position A is held.

  As described above, the secondary transfer device 60 is rotated and the abutting portion 65 is abutted against the positioning projection 66 of the fixing device 40, so that the secondary transfer device 60 is held at the operating position A. The secondary transfer device 60 and the fixing device 40 can be directly positioned and the parallelism of each other can be ensured by eliminating the accumulation of tolerances without going through the housing. Therefore, the relative positional accuracy between the secondary transfer device 60 and the fixing device 40 is increased without causing an increase in cost, and the possibility of curling or wrinkling in the transfer material P or color misregistration in the toner image is eliminated. be able to. As a matter of course, the abutting position is preferably set to a position where the accumulation of tolerances is minimized.

  When the secondary transfer device 60 is in the operating position A, the transfer material P is sent out by the registration roller pair 36 in synchronization with the toner image on the transfer belt 10, and the transfer entrance guide member 62 is passed through the conveyance path 32. The toner image on the transfer belt 10 is transferred by the secondary transfer roller 34 at the secondary transfer position N2, and the transfer material P after the image transfer is transferred to the transfer exit guide. It is guided by the member 63 and fed into the fixing device 40 from the introduction port 42.

  The transfer material P fed into the fixing device 40 is guided by the fixing inlet guide member 57 and passes through the fixing nip N, where heat and pressure are applied, and the unfixed toner T is applied to the transfer material P as shown in FIG. The toner is fixed, separated from the fixing belt 50 by the separation member 59, guided by the fixing outlet guide member 58, and discharged from the discharge port 43.

  A transfer outlet guide member 63 for guiding the transfer material P after image transfer from the secondary transfer device 60 and a fixing inlet guide member 57 for guiding the transfer material P after image transfer to the fixing device 40 are as follows: In this example, they are separate bodies and are attached to the casing 61 of the secondary transfer device 60 and the casing 41 of the fixing device 40, respectively, but their guide members 63 and 57 are integrated as one of the devices 60 and 40. You may make it attach to. A separate body can set the optimum transport path 32, but there is a cost merit when integrated. In addition, since the positioning is performed on the secondary transfer device 60 and the fixing device 40, there is an advantage that it is easy to set a step, a gap, or the like of the connecting portion of both guide members.

6A and 6B show a state in which the pressure roller 54 is configured to be displaced relative to the fixing roller 44, respectively.
That is, the pressure roller 54 is in contact with the fixing roller 44 when the thickness of the transfer material P fluctuates as shown in FIG. 6A or when it thermally expands as shown in FIG. The shaft 53 is supported so as to be moved in the left-right direction so as to be close to and away from each other, and is configured to be pressed against the outer peripheral surface of the fixing roller 44 via the fixing belt 50 by a biasing means such as a spring (not shown). .

FIG. 7 shows another example of the present invention in which a transfer outlet guide member 63 and a fixing inlet guide member 57 are provided so that their positions can be adjusted.
The transfer outlet guide member 63 is supported so as to be rotatable about the support shaft 70. Similarly, the fixing inlet guide member 57 is also supported rotatably about the support shaft 71. In the example shown in FIG. 7, both guide members 63 and 57 are urged by the tension springs 72 and 73, respectively, but these springs may not be provided.

  When the transfer material P is wrinkled or bent, it can be dealt with by changing the conveyance path 32 of the transfer material P. That is, when the transfer material P is wrinkled or bent, the angle of the fixing inlet guide member 57 is appropriately changed to adjust the position of the fixing inlet guide member 57. Although not shown, the support shaft 71 is provided with a set screw, and the fixing entrance guide member 57 is adjusted by adjusting the angle of the fixing entrance guide member 57 by loosening the set screw and tightening the set screw. The position of the member 57 is fixed at that angle. The position adjustment of the transfer outlet guide member 63 is performed in the same manner.

FIG. 8 shows still another example of the present invention in which the transfer outlet guide member 63 and the fixing inlet guide member 57 are provided so as to be capable of adjusting the position in conjunction with each other.
Similarly, the transfer outlet guide member 63 is supported to be rotatable about a support shaft 70, and the fixing inlet guide member 57 is also supported to be rotatable about a support shaft 71. Both guide members 63, 57 are They are biased by tension springs 72 and 73, respectively.

  However, in this example, there is no set screw at the positions of the support shafts 70 and 71, and the urging force of the tension spring 73 is superior to the urging force of the tension spring 72, so that the transfer outlet guide member 63 is always connected to the fixing inlet guide member 57. It comes to contact. A solenoid 75 is connected to the fixing inlet guide member 57 via a link 74.

  As a result, when the solenoid 75 is turned on, the link 74 is pulled and moved rightward, the fixing inlet guide member 57 rotates counterclockwise about the support shaft 71, and the transfer outlet guide member 63 is moved to the right. Following this, it is rotated clockwise around the support shaft 70, and is changed from the chain line position to the solid line position in the figure, so that both guide members 57, 63 are arranged in reverse "<".

  On the contrary, when the solenoid 75 is turned off, the fixing inlet guide member 57 is returned clockwise by the urging force of the tension spring 73 and the link 74 is fully pulled out, and the transfer outlet guide member 63 is pushed back counterclockwise. Thus, the position of the chain line is changed from the position of the solid line in the figure.

  In this example, the position adjustment of both the guide members 57 and 63 is performed by the link 74 and the solenoid 75, but the drive device is not limited to the solenoid. For example, if a drive device comprising a motor, a cam, and a link is used, It is also possible to finely adjust the positions of both guide members 57 and 63. Further, the guide members 57 and 63 may be manually adjusted with a manual lever.

  In the example shown in FIG. 8, the biasing force of the tension spring 73 is superior to the biasing force of the tension spring 72, and the transfer outlet guide member 63 is always in contact with the fixing inlet guide member 57. However, as shown in FIG. 9, for example, the transfer outlet guide member 63 and the fixing inlet guide member 57 are engaged with each other in a comb-like shape, and are connected to each other by a common shaft 76 at the engagement position. May be.

  The transfer outlet guide member 63 and the fixing inlet guide member 57 are preferably provided so that their positions can be adjusted according to the sheet passing conditions. Here, examples of the sheet passing condition include single-sided paper passing and double-sided paper passing during copying and copying. For example, in the case of double-sided paper passing, since the transfer material that has once passed through the fixing device is transported again to the fixing device, the curling may be transported to the fixing device. When the curl of the transfer material is large, the ears are folded or wrinkled. At this time, if the position of the fixing entrance guide member 57 is adjusted to a position suitable for the conveyance of the curled transfer material, the ear folds and wrinkles can be reduced. Specifically, when the curl is large on the non-image surface side, both guide members 57 and 63 may be moved as indicated by a chain line in FIG.

  In addition to this, there are differences in the conveyance speed as the paper passing conditions. There are cases where the transfer speed of the transfer material is properly used in several stages in order to change the resolution and finish. For example, there are cases where three speeds of 222 mm / s, 125 mm / s, and 62.5 mm / s are properly used. Also in this case, the state of the tip of the transfer material varies depending on the transfer speed of the transfer material. That is, in detail, since the transfer material after transfer is charged, it is conveyed while sticking to the above-described guide members 57 and 63, for example. When the transport speed is fast, the tip is transported in a floating manner, and when the transport speed is slow, the tip is transported in a sticky manner. This can also reduce the above-mentioned problems by adjusting the positions of the guide members 57 and 63. Specifically, when the transfer material is sticky, both guide members 57 and 63 may be moved as indicated by the solid line in FIG.

  In addition, when double-sided paper is passed, the first surface (the image created first) may rub against the guide members 57 and 63. Similarly, by adjusting the positions of the guide members 57 and 63, the rubbed image is displayed. Can be reduced.

  The transfer outlet guide member 63 and the fixing inlet guide member 57 may be provided so that their positions can be adjusted depending on the type of transfer material. The types of transfer materials are mainly the types of transfer materials (paper, resin sheet, coated paper, label paper, envelope, backing paper, recycled paper, etc.), thickness, waist strength (rigidity), electrical resistance, and roughness. And so on. Since the user uses various transfer materials, it is difficult to give a corresponding example here. However, it is conceivable that some positions of the guide members 57 and 63 can be set in advance and an optimum setting is selected from the settings. In this case, if it is a printer, it may be set by a printer driver, or may be selected from the operation panel. When the brand of the transfer material is selected, the guide members 57 and 63 may be moved to the optimum position.

  Further, the transfer outlet guide member 63 and the fixing inlet guide member 57 may be provided so that their positions can be adjusted depending on the installation environment conditions. The installation environment conditions are mainly the usage environment (temperature / humidity, humidity control state of transfer paper) of a machine such as a printer or a copying machine. When the humidity is high, the transfer material tends to curl. Further, since the transfer conditions change depending on the humidity, the charge amount of the transfer material also changes. By setting an optimal guide member position for these, wrinkles and broken ears can be improved. When the charge amount is large, the guide members 57 and 63 may be moved as shown by the chain line in FIG.

  Further, the transfer outlet guide member 63 and the fixing inlet guide member 57 may be provided so that their positions can be adjusted according to the image conditions of the transfer material. The image condition is mainly an image area, a picture quality, and the like. When the image area is large, the charge amount of the transfer material increases. In addition, the amount of toner may be increased even in photographic quality, which affects the charge amount. When these conditions overlap with double-sided paper feeding, it often affects the conveyance, so that the countermeasure by adjusting the guide members 57 and 63 is effective.

1 is an overall schematic configuration diagram of an internal mechanism of a tandem color printer which is an example of an electrophotographic image forming apparatus. FIG. 3 is an enlarged configuration diagram of image forming means provided in the color printer. It is a schematic block diagram of one image forming unit with which the image forming means is provided. FIG. 2 is a schematic configuration diagram of a fixing device provided in the color printer of FIG. 1. FIG. 5 is a configuration diagram of a secondary transfer device shown together with the fixing device of FIG. 4. (A) And (B) is a figure which shows the state respectively comprised so that a pressure roller may be displaced relatively with respect to a fixing roller. It is a figure which shows the other example of this invention in which the transfer exit guide member and the fixing entrance guide member are provided so that position adjustment is possible. FIG. 10 is a view showing still another example of the present invention in which a transfer outlet guide member and a fixing inlet guide member are provided so as to be capable of adjusting their positions in conjunction with each other. It is the front view and side view of a connection guide member which show the modification of FIG.

Explanation of symbols

10 Intermediate transfer belt (image carrier)
34 Secondary transfer roller 40 Fixing device 57 Fixing entrance guide member 60 Secondary transfer device 63 Transfer exit guide member 64 Support shaft 65 Abutting portion 66 Positioning projection A Operating position B Retraction position P Transfer material T Unfixed toner

Claims (8)

In an image forming apparatus in which a toner image on an image carrier is transferred to a transfer material by a transfer device, and then the transfer material is passed through a fixing device and unfixed toner on the transfer material is fixed to the transfer material by the fixing device. ,
The transfer device is provided movably between an operating position and a retracted position, and an abutting portion that is held at the operating position by being abutted against the fixing device is formed in the transfer device. Forming equipment.   A transfer outlet guide member that guides when a transfer material after image transfer is sent out from the transfer device, and a fixing inlet guide member that guides when a transfer material after image transfer is received by the fixing device, The image forming apparatus according to claim 1.   The image forming apparatus according to claim 2, wherein both the transfer outlet guide member and the fixing inlet guide member are provided so as to be adjustable in position.   The image forming apparatus according to claim 3, wherein the transfer outlet guide member and the fixing inlet guide member are provided so as to interlock with each other.   5. The image forming apparatus according to claim 3, wherein the transfer outlet guide member and the fixing inlet guide member are provided so as to be position-adjustable depending on paper passing conditions.   5. The image forming apparatus according to claim 3, wherein the transfer outlet guide member and the fixing inlet guide member are provided so that their positions can be adjusted depending on the type of transfer material.   5. The image forming apparatus according to claim 3, wherein the transfer outlet guide member and the fixing inlet guide member are provided so as to be adjustable in position according to installation environment conditions. 6.   5. The image forming apparatus according to claim 3, wherein the transfer outlet guide member and the fixing inlet guide member are provided so as to be position-adjustable according to image conditions of the transfer material.

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