JP2006011184A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately handle a jamming recording material by improving visibility and operability for a jam occurring during feeding, transfer, and fixation even with small-sized, simple constitution. <P>SOLUTION: In the image forming apparatus wherein a feeding device 60 which supplies the recording material P, a secondary transfer roller 2 which transfers a visible image on an intermediate transfer belt 10 to the recording material P fed by the feeding device 60, and a fixing device 50 which fixes the visible image transferred from the intermediate transfer belt 10 by the secondary transfer roller 2 to the recording material P are arranged upward in this order nearly perpendicularly, and a conveyance path for the recording material is formed among them, a door 3 capable of opening the inner side is provided at a portion of a device housing and the intermediate transfer belt 10 and secondary transfer roller 2 can move toward the opening part where the door 3 is opened while having nearly the same position relation with image formation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine using an electrophotographic process.

  Image forming apparatuses such as copiers, printers, fax machines, etc. often use toner-based electrophotographic methods, and in recent years, their forms such as colorization have become diversified as information devices become more sophisticated and functional. Yes.

  The usage forms of these image forming apparatuses are installed on a dedicated cart or a normal desk, and a user operates these apparatuses in an upright posture such as access to documents before and after recording and jam processing. It is customary. In particular, the recording material discharge unit used most frequently in these apparatuses satisfies the operability of many users, that is, its height is naturally limited from the viewpoint of usability.

  For example, in the case of a small woman with an extension of about 150 cm, the presence or absence of the recording material in the recording material discharging portion cannot be confirmed if there is no recording material discharging portion at least at a position lower than 140 cm in consideration of the eye height. . Furthermore, considering the viewpoints of wheelchair users and children from the viewpoint of universal design, a lower discharge position of about 120 to 130 cm is required.

  In addition, a so-called desktop type that can be installed on a normal desk without providing a dedicated carriage is the mainstream as a form of the above-described device from the trend of cost reduction. Therefore, taking into account that the desk height is usually about 650 mm to 700 mm, it is ideal that the recording material discharge portion of the apparatus is suppressed to 500 to 600 mm or less from the desk surface.

  As an example of a configuration that satisfies these conditions, there is a method of providing a discharge tray as the recording material discharge unit 70 on the side surface of the image forming apparatus main body as shown in FIG. However, when such a configuration is used, the recording material discharge portion 70 extending from the side surface of the apparatus main body increases the installation area of the apparatus, and a new problem has arisen that it is difficult to install in a small office environment.

  Further, when the recording material discharge unit 70 is provided on the side surface of the main body, the arrangement in the main body of the fixing device 50 arranged upstream in the conveyance direction of the recording material conveyance path following the recording material discharge unit 70 is also below the image forming apparatus. It must be placed. Therefore, the heat from the fixing device 50 rises due to the convection, and the temperature of other devices such as the process units 21, 22, 23, 24 above the fixing device 50 is raised. . Therefore, in the image forming apparatus having the above configuration, many electric fans and the like are inevitably added, resulting in further enlargement of the apparatus and high cost.

  In recent years, a method for solving the problem of the installation area and the temperature rise in the apparatus by using an apparatus configuration as disclosed in Japanese Patent No. 2941858 has been proposed. In this apparatus configuration, a paper discharge tray as a recording material discharge unit is provided on the upper surface of the printer main body, a fixing device as a fixing device is disposed above the printer main body, and a photosensitive drum as an image carrier and a transfer device are provided below the fixing device. A so-called vertical path configuration in which a feeding device including a transfer roller, a feeding roller, and the like is arranged, and the feeding device, the transfer device, and the fixing device are sequentially positioned in accordance with the conveyance of the recording material. By using this, the influence of heat from the fixing device to other devices is reduced.

  However, when the above-mentioned height compatibility from the viewpoint of usability and the above-described configuration that achieves both the temperature rise and the vertical path configuration as a means for solving the installation area are squeezed, the recording material conveyance continues with feeding, transferring, and fixing. The problem is that the path is inevitably shortened, and the operability with respect to the processing of the jam occurring at this point is remarkably lowered.

  As one means for solving this problem, Japanese Patent Application Laid-Open No. 4-56969 proposes a configuration in which a door that can divide and open the recording material conveyance path following feeding, transferring, and fixing is proposed. FIG. 9 shows an example of a color image forming apparatus to which the above proposal is applied.

  As can be understood from FIG. 9, in this configuration, the transfer device 2 must be disposed on the door 3 side, and the transfer device 2 on the door 3 side faces the transfer device 2 in order to ensure transferability. High fitting accuracy is required between the image carrier 10 on the apparatus main body side, and high rigidity and assembly accuracy are required on the door 3 side. Further, when the transfer device 2 is also used as a conveying means for the recording material P, it is necessary to provide its driving means (not shown) and at least a gear train (not shown) for transmitting driving on the door 3 side. There is also a need for a drive coupling mechanism, and coupled with the high rigidity and accuracy requirements described above, the door 3 itself becomes heavy, which increases costs.

  In addition, even when the door 3 is opened and the recording material conveyance path is opened during the jam processing, the recording material conveyance path is opened from the standpoint of the upright operator by the fixing device 50 arranged at the upper part of the apparatus main body. Because it is hidden, it must be jammed in a narrow part that is difficult to see, and it cannot be said that the operability is good. Further, a recording material conveyance path having a vertical path configuration that leads to a feeding device 60 composed of feeding rollers 61 to 63, a transfer device 2 composed of a transfer roller, and a fixing device 50 composed of a fixing roller 51 and a pressure roller 52, Since the recording apparatus P becomes shorter as the apparatus becomes smaller, the frequency of occurrence of a jam in a state where the recording material P is held by all of the feeding apparatus 60, the image carrier 10, the transfer apparatus 2, and the fixing apparatus 50 is increased. In particular, when such a jam occurs, the recording material P needs to be taken out from the fixing device 50 by pulling the recording material from the opening portion where the door 3 is opened in the direction opposite to the recording material conveyance direction, and vice versa. In addition, it is necessary to pull out the recording material from the feeding device 60 in the recording material conveyance direction, which is difficult to see and very complicated as a work in a narrow space.

Japanese Patent No. 2941858 JP-A-4-56969

  In view of the above problems, the present invention can improve the visibility and operability of a jam that occurs between feeding, transferring, and fixing even with a small and inexpensive main body configuration, and can accurately handle a jammed recording material. An object is to provide an image forming apparatus.

  A typical configuration of the present invention for achieving the above object includes a feeding device that supplies a recording material, an image carrier that carries a visible image transferred to the recording material fed by the feeding device, and A transfer device for transferring a visible image on the image carrier to the recording material fed by the feeding device; a fixing device for fixing the visible image transferred from the image carrier by the transfer device to the recording material; In the image forming apparatus in which the feeding device, the transfer device, and the fixing device are arranged in a substantially vertical direction from the lower side to the upper side in this order, and a recording material conveyance path is formed between these devices. An opening part that can be opened inside is provided in a part of the housing, and at least the image carrier and the transfer device can move toward the opening part in substantially the same relative positional relationship as in image formation. Features.

  According to the present invention, not only an opening portion that can be opened inside is provided in a part of the apparatus housing, but also at least the image carrier and the transfer device are separated from the opening portion in substantially the same relative positional relationship as during image formation. Since it is constructed so that it can be pulled out, it is not only a compact and inexpensive main body structure, but it can also easily recognize jammed recording materials during feeding, transfer, and fixing, and remove jammed recording materials, etc. Jam processing can be performed accurately and easily.

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

[First Embodiment]
The image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view showing a tandem color image forming apparatus according to the first embodiment of the present invention. FIG. 2 is a schematic plan view showing a situation in which the arrangement of the intermediate transfer belt unit 1 and its drive source M in the image forming apparatus according to the first embodiment of the present invention is viewed from the direction of arrow A in FIG. FIG. 3 is an enlarged cross-sectional view of the main part showing the fixing device and the pressure reducing means according to the first embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view of a main part showing the feeding device and holding force reducing means according to the first embodiment of the present invention. FIG. 5 is an explanatory diagram showing a jam processing procedure of the image forming apparatus according to the first embodiment of the present invention. Hereinafter, the present embodiment will be described with reference to these drawings.

  First, a schematic configuration and an image forming process of the image forming apparatus according to the first embodiment of the present invention will be briefly described.

  In FIG. 1, reference numerals 21, 22, 23, and 24 denote process units (cartridges), respectively. Since the configuration of these process units 21, 22, 23, and 24 is the same, image formation in each process unit will be outlined below using the process unit 24.

  In the process unit 24, a photosensitive drum 240 carrying an electrostatic latent image, a charging roller 242 for uniformly charging the photosensitive drum 240, and the electrostatic latent image on the photosensitive drum 240 by a developer (not shown). A developing roller 241 for visualizing and a cleaner 243 for removing residual developer on the photosensitive drum 240 after the visible image is transferred to the intermediate transfer belt 10 as an image carrier are disposed. In this apparatus, process units 21, 22, 23 and 24 having the same configuration are arranged in series on the intermediate transfer belt 10. Each process unit 21 to 24 contains a developer of a different color. The exposure for each process unit 21 to 24 is performed on the photosensitive drum 240 of each process unit by an exposure device 31, 32, 33, 34 corresponding to each process unit according to the image signal of each color. . Visible images on the photosensitive drums 240 created by the processes that follow charging, exposure, and development in the process units 21 to 24 are transferred to the photosensitive drums 240 by the primary transfer rollers 13 facing the photosensitive drums 240. Are sequentially transferred onto the intermediate transfer belt 10 (primary transfer). The superimposed image on the intermediate transfer belt 10 is conveyed to a position opposite to the secondary transfer roller 2 as a transfer device as the intermediate transfer belt 10 rotates, and the recording sent from the feeding device 60 in synchronization therewith. Transferred to the material P by the secondary transfer roller 2. The developer on the intermediate transfer belt 10 that has not been secondarily transferred is removed by the belt cleaner 12. In addition, the superimposed image transferred to the recording material P is conveyed to the fixing device 50 and is subjected to pressure and heat treatment to become a permanent image. The recording material P on which the image has been fixed is discharged and stacked on the recording material discharge unit 70 at the top of the apparatus.

  The feeding device 60, the secondary transfer roller 2, and the fixing device 50 are arranged in a substantially vertical direction in order from the bottom to the top, and a conveyance path for the recording material is formed therebetween.

  Next, a characteristic configuration of the image forming apparatus according to the first embodiment of the present invention will be described in detail.

  In FIG. 1 and FIG. 2, the intermediate transfer belt 10 as an image carrier is biaxially stretched between a driving roller 14 and a driven roller 11, and these rollers 14 and 11 sandwich the intermediate transfer belt 10. It is supported by inner sheet metals 15 and 16 arranged at both ends in the longitudinal direction. A belt cleaner 12 having the driven roller 11 as a counter roller and a secondary transfer roller 2 as a secondary transfer device are also supported on the inner metal plates 15 and 16. The inner metal plates 15 and 16 determine the arrangement of members related to the conveyance of the recording material P in the secondary transfer portion. In this way, the intermediate transfer belt unit 1 is configured.

  The intermediate transfer belt unit 1 unitized as described above includes unit guides 17 and 18 provided on the inner metal plates 15 and 16 and main body guides 19 and 20 provided on a main body side metal plate (not shown). Are supported in the main body, and the unit guides 17 and 18 can be slid along the main body guides 19 and 20 in the direction of arrow B in FIG. In other words, the intermediate transfer belt 10 as an image carrier and the secondary transfer roller 2 as a transfer device are configured to be movable in the direction of arrow B with substantially the same relative positional relationship as during image formation.

  Further, as shown in FIG. 2, a driving gear G <b> 1 for obtaining driving from the apparatus main body is disposed at the end of the driving roller 14 positioned outside the inner sheet metals 15, 16, and the outer side of the inner sheet metals 15, 16. The drive gear G1 and the drive gear G2 from the main body drive source M are fitted in the same direction as the slide direction (arrow B direction) of the intermediate transfer belt unit 1 so that the drive to the intermediate transfer belt 10 can be obtained. It has become.

  Accordingly, the intermediate transfer belt unit 1 is configured to be able to release the drive from the main body drive source M to the drive roller 14 by being pulled out of the apparatus along the main body guides 19 and 20 in the direction of arrow B in the figure. Yes.

  Further, as shown in FIG. 1, a door 3 as an opening part that can be opened inside is provided in a part of the apparatus housing. The door 3 is for forming an opening through which a part of the intermediate transfer belt unit 1 can be taken out from the main body casing in the moving direction of the intermediate transfer belt unit 1 of the main body casing. Although the inner surface of the door 3 also serves as a part of the recording material conveyance path in the apparatus, the door 3 is not provided with a drive train or a gear train that transmits power, so that it is extremely simple. It has become a structure.

  Next, the configuration of the fixing device 50 in the image forming apparatus will be described in detail with reference to FIG. As shown in FIG. 3, the fixing device 50 is provided with a fixing roller pressure releasing mechanism (pressure reducing means) that can release the pressure between the fixing roller 51 and the pressure roller 52 as described below. Yes. The fixing device 50 includes a fixing frame 59 that rotatably supports a fixing roller 51 as a fixing member, and a pressure frame 54 as a swinging member that rotatably supports the pressure roller 51 as a pressure member. ing. The pressure frame 54 is swingably supported by a support shaft 53 fixed to the fixing frame 59, and is urged so that the pressure roller 52 is pressed against the fixing roller 51 by a pressure spring 56 as a pressure unit. Has been. Further, a cam 55 as a pressure release means is provided at a position where the pressure spring 56 faces the pressure frame 54. The cam 55 is fixed to a cam shaft 58 that is rotatably supported by the fixing frame 59, and rotates integrally with the cam shaft 58. A fixing roller pressure release lever 57 that rotates a cam 55 integrated with the cam shaft 58 is fixed to the cam shaft 58.

  In the fixing roller pressure releasing mechanism configured as described above, the cam 55 is rotated integrally by rotating the fixing roller pressure releasing lever 57 in the direction of the arrow in FIG. Then, the rotating cam 55 swings the pressure frame 54 against the urging force of the pressure spring 56, and is supported by the pressure roller 51 supported by the pressure frame 54 and the fixing frame 59. The pressure applied to the fixing roller 51 is reduced.

  The fixing roller pressure releasing lever 57 in the fixing roller pressure releasing mechanism is disposed at a position where the door 3 can be seen from the top of the main body by opening the door 3 as can be understood from FIG. When the jammed recording material P stays between the fixing roller 51 and the pressure roller 52, the holding force can be easily released using these pressure release levers 57.

  Next, the configuration of the feeding device 60 in the image forming apparatus will be described in detail with reference to FIG. As shown in FIG. 4, the feeding device 60 is provided with a feeding roller pressure releasing mechanism (holding force reducing means) for reducing the recording material holding force by the feeding device as described below. The feeding roller 62 of the feeding device 60 is rotatably supported by the feeding-side sheet metal 65 via a bearing. The feed roller 62 is driven by a feed drive motor (not shown) through a gear train (not shown) to a gear (not shown) fixed to the end of the feed roller 62. A feeding roller 63 facing the feeding roller 62 is also rotatably supported on the feeding side metal plate 65 via a bearing. Further, the bearing portion 67 of the feeding roller 63 is formed as a long hole that can move in the direction toward the feeding roller 62 within the surface of the feeding-side sheet metal 65. A pressure spring 66 that surrounds the feeding roller 63 from the feeding sheet metal 68 and pressurizes the feeding roller 63 toward the feeding roller 62 is provided on the feeding roller 63. It is provided at both ends of the part. A lever 64 that is positioned on the inner side in the longitudinal direction of the feeding roller 62 with respect to the pressure spring 66 and is rotatably attached to the shaft of the feeding roller 62 serves as a pressure release unit that releases the pressure applied to the feeding roller 63. This is a feed roller pressure release lever. The feeding roller pressure release lever 64 includes an eccentric cam portion 641 that rotates integrally with the lever 64 around the axis of the feeding roller 62. In the figure, reference numeral 80 denotes a feeding cassette for loading and storing the recording material P, and 61 denotes a feeding roller for feeding out the recording materials P stacked and accommodated in the feeding cassette 80 one by one.

  In the feed roller pressure release mechanism configured as described above, the eccentric cam portion 641 rotates integrally by turning the feed roller pressure release lever 64 in the direction of the arrow in FIG. The rotating eccentric cam portion 641 abuts on the feeding roller 63 and moves the feeding roller 63 in a direction opposite to the pressurizing direction of the pressure spring 66, so that the feeding roller 62 and the feeding roller 63 are fed. The pressing force between the rollers 63 is reduced.

  Further, the feed roller pressure release lever 64 in the feed roller pressure release mechanism is arranged at a position where the door 3 can be seen from the top of the main body by opening the door 3 as can be understood from FIG. When the jammed recording material P stays between the feeding rollers 62 and 63, the holding force can be easily released using these pressure release levers 64.

  Next, the recording material jam processing in the configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG.

  When the recording material P is jammed in the image forming apparatus according to the present embodiment described above, the recording material P is fed to the feeding rollers 62 and 63 in the feeding device 60 and the intermediate transfer belt 10 and the secondary transfer belt in the intermediate transfer belt unit 1. It is held between the fixing roller 51 and the pressure roller 52 in the apparatus 2 and the fixing device 50. The procedure of the jam processing at this time is as follows (1) to (5).

  (1) Open the door 3 in the direction of the arrow.

  (2) Using the fixing roller pressure release lever 57 of the fixing device 50, the pressure applied between the fixing roller 51 and the pressure roller 52 forming the fixing roller pair is released.

  (3) Using the feeding roller pressure release lever 64 of the feeding device 60, the pressure applied to the pair of feeding rollers 62 and 63 is released.

  (4) The intermediate transfer belt unit 1 in which the intermediate transfer belt 10 and the secondary transfer roller 2 are integrated is pulled out toward the opening opened by the door 3.

  (5) The recording material P sandwiched between the intermediate transfer belt 10 and the secondary transfer roller 2 moved out of the apparatus together with the intermediate transfer belt unit 1 in the procedure (4) is pulled out in the transport direction.

  As described above, according to the present embodiment, not only the door 3 that can be opened inside is provided in a part of the apparatus housing, but the intermediate transfer belt 10 and the secondary transfer roller 2 are substantially the same as those at the time of image formation. Since the door 3 can be pulled out from the opened opening with the same relative positional relationship, the jammed recording material P is not processed at a deep position inside the main body, but the user visually recognizes the recording material P. Processing can be performed after taking out to an easy position, and workability is improved. In addition to a compact and inexpensive main body configuration, the jammed recording material P can be easily recognized and the jammed recording material P can be easily removed while feeding, transferring and fixing. It can be done accurately and easily.

  In the present embodiment, a color image forming apparatus is illustrated, but the present invention is not limited to this, and may be, for example, a monochrome image forming apparatus. In the monochrome image forming apparatus, an image carrier is used. As in the intermediate transfer belt unit 1 described above, the electrophotographic photosensitive member and the transfer device for transferring the image on the electrophotographic photosensitive member to the recording material can be moved in substantially the same relative positional relationship as in the image formation. By using the photoconductor unit, the same effect can be obtained.

  In this embodiment, the printer is exemplified as the image forming apparatus. However, the present invention is not limited to this, and other image forming apparatuses such as a copying machine and a facsimile apparatus, or a combination of these functions. The image forming apparatus may be another image forming apparatus such as a multifunction peripheral, and the same effect can be obtained by applying the present invention to the image forming apparatus.

[Second Embodiment]
An image forming apparatus according to the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a drive transmission diagram of the feeding device in the image forming apparatus according to the second embodiment of the present invention.

  In the above-described embodiment, the feeding roller pressure releasing mechanism shown in FIG. 4 is exemplified as the holding force reducing means for reducing the recording material holding force by the feeding device, but the invention is not limited to this. In the present embodiment, as a holding force reducing unit of the feeding device, there is a drive cutting unit that cuts a driving path to the feeding device from its driving source. Hereinafter, the drive cutting means as the holding force reducing means will be described.

  In FIG. 6, the driving to the feeding roller 61 is transmitted from the feeding motor 81 as a driving source to the gear G13 via the gears G11 and G12. The feed roller 62 and the feed roller 63 forming the feed roller pair are driven and cut from the feed motor 81 as the drive source through the gears G11 and G14 to the gears G15 to G18 as the final transmission unit. It is transmitted via a one-way clutch 82 as a means. When the recording material P is pulled out in the transport direction in a jammed state where the recording material P is nipped by the feeding device 60 by the one-way clutch 82 as the drive cutting means, the feeding roller 62 and the feeding roller 63 are The connection is released from the drive system having a large rotational inertia, and the driven rotation is enabled according to the moving amount by which the recording material P is pulled out as a jam process. Therefore, when the jammed recording material P is pulled out, the holding force for holding the recording material P of the feeding device 60 is reduced by the driven rotation of the feeding roller 62 and the feeding roller 63, and the recording force is reduced between the drawing force and the recording force. The material P is kept small enough not to break. As described above, the one-way clutch 82 as the drive cutting unit in the present embodiment acts as a holding force reducing unit that reduces the holding force of the recording material P of the feeding device 60 when the recording material P is pulled out in the feeding direction. To do.

  When the above configuration is used, the recording material P can be rotated by the tension generated in the recording material P by pulling out the intermediate transfer belt unit 1 in the jam processing procedure (4) described in the first embodiment. It is pulled out from the feeding device 60 in the recording material conveyance direction. Therefore, in the configuration using this embodiment, it is not necessary to release the pressure applied to the pair of feeding rollers performed in the jam processing procedure (3) shown in the first embodiment described above. The number of man-hours during the jam processing can be reduced, and the jam processing performance can be further improved.

  In the present embodiment, the case where the one-way clutch (drive disconnecting means) 82 is used in the feeding drive system as the holding force reducing means is exemplified, but the present invention is not limited to this. When the recording material P straddling between the feeding device 60 and the transfer device 2 is pulled out at least during jam processing, the recording material P holding force of the feeding device 60 is broken between the pulling force and the recording material P. A known technique can be applied to this as long as it is a means that is kept small enough not to occur.

  Unlike the present embodiment, in the image forming apparatus in which the driving to the feeding roller 62 and the feeding roller 63 is controlled by an electromagnetic clutch, such means as not to excite the electromagnetic clutch during the jam processing is retained. You may use as a force reduction means (drive cutting means).

  In addition, when the driving source of the feeding roller 62 and the feeding roller 63 is a small motor or the like, since the inertia when the motor is not excited is small, means for not exciting the motor at least during jam processing is also available. It may be used as a holding force reducing means.

[Third Embodiment]
An image forming apparatus according to the third embodiment of the present invention will be described with reference to FIG. FIG. 7 is an enlarged cross-sectional view of the main part showing the pressure reducing means of the fixing device in the image forming apparatus according to the third embodiment of the present invention. FIG. 7 is a cross-sectional view of the image forming apparatus shown in the first embodiment as viewed from the back of the main body opposite to the front of the main body in FIG.

  In the above-described embodiment, as the pressure reduction means in the fixing device, the fixing roller pressure that releases the pressure between the fixing roller 51 and the pressure roller 52 by manually rotating the fixing roller pressure release lever 57 by the user. Although the release mechanism (see FIG. 3) has been illustrated, the present invention is not limited to this. In the present embodiment, the pressure reduction means includes a drive source as the pressure reduction means of the fixing device, and when the jam is detected, the drive source is operated to release the pressure of the fixing device prior to the jam processing. I am doing so. Hereinafter, the pressure reducing means of the fixing device according to the present embodiment will be described.

  In the present embodiment, a drive gear 91 for driving the cam shaft 58 is fixed to the back side of the fixing device main body of the cam shaft 58 of the cam 55 shown in the first embodiment. The drive gear 91 is engaged with a drive gear 92 that is driven by a separation motor 90 as a drive source that operates in accordance with an instruction from a main body CPU (not shown).

  The separation motor 90 as the drive source rotates in accordance with an instruction from the main body CPU, and the phase of the cam 55 serving as the output end of the cam 55 is in a pressurized state and a released state in which the phase is 90 ° different from the pressurized state. It is possible to make transition to these two states. Specifically, the phase control of the cam 55 is instructed by the main body CPU so that the image forming apparatus maintains a pressurized state when an image is formed and maintains a released state when a non-image is formed or when a jam occurs. .

  Therefore, in the configuration using this embodiment, it is not necessary for the user to release the pressure applied to the fixing roller pair of the fixing device 50, which is the jam processing procedure (2) shown in the first embodiment. Compared to the first embodiment described above, the number of man-hours during the jam processing can be reduced, and the jam processing performance can be further improved.

1 is a schematic cross-sectional view showing a tandem color image forming apparatus according to a first embodiment. FIG. 1 is a schematic plan view showing the arrangement of an intermediate transfer belt unit and its drive source in the image forming apparatus according to the first embodiment viewed from the direction of arrow A in FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing the fixing device and the pressure reducing means according to the first embodiment. The principal part expanded sectional view which shows the feeding apparatus and holding force reduction means which concern on 1st Embodiment. Explanatory drawing which shows the jam processing procedure of the image forming apparatus which concerns on 1st Embodiment. Drive transmission diagram of feeding device in image forming apparatus according to second embodiment The principal part expanded sectional view which shows the fixing device and pressurizing force reduction means in the image forming apparatus which concerns on 3rd Embodiment. Schematic cross-sectional view of a conventional color image forming apparatus Schematic cross-sectional view of a conventional color image forming apparatus

Explanation of symbols

M: Main body drive source P ... Recording material 1 ... Intermediate transfer belt unit 2 ... Secondary transfer roller (transfer device)
3 ... Door (opening part)
10: Intermediate transfer belt (image carrier)
11 ... driven roller 12 ... belt cleaner 13 ... primary transfer roller 14 ... drive rollers 15 and 16 ... inner sheet metals 17 and 18 ... unit guides 19 and 20 ... main body guides 21, 22, 23, and 24 ... process units 31, 32, 33, 34 ... Exposure device 50 ... Fixing device 57 ... Fixing roller pressure release lever 60 ... Feeding device 62, 63 ... Feeding roller 64 ... Feeding roller pressure release lever 641 ... Eccentric cam portion 65 ... Feeding side sheet metal 70 ... Recording material discharge unit 81 ... feeding motor 82 ... one-way clutch 90 ... separation motors 91 and 92 ... drive gear

Claims (7)

A feeding device for supplying a recording material; an image carrier for carrying a visible image transferred to the recording material fed by the feeding device; and the image carrier for the recording material fed by the feeding device A transfer device that transfers the visible image above, and a fixing device that fixes the visible image transferred from the image carrier by the transfer device to a recording material, in the order of the feeding device, the transfer device, and the fixing device. In the image forming apparatus in which a recording material conveyance path is formed between these apparatuses, which is arranged in a substantially vertical direction from the lower side to the upper side.
An opening portion that can be opened inside is provided in a part of the apparatus casing, and at least the image carrier and the transfer device can move toward the opening portion in the same relative positional relationship as at the time of image formation. An image forming apparatus.   2. The image forming apparatus according to claim 1, further comprising holding force reducing means for reducing a recording material holding force by the feeding device when the jammed recording material is pulled out from at least the transfer device side in the recording material conveyance direction.   The image forming apparatus according to claim 2, further comprising: a driving cutting unit that cuts a driving path to the feeding device from a driving source as the holding force reducing unit.   The image forming apparatus according to claim 3, wherein the drive disconnecting unit is a one-way clutch.   The image forming apparatus according to claim 3, wherein the drive disconnecting unit is an electromagnetic clutch.   The fixing device is a device in which a fixing member and a pressure member are pressurized by a pressure unit, and a recording material passes between these members to fix an image. At least at the time of jam processing, a pressure applied by the pressure unit The image forming apparatus according to claim 1, further comprising a pressure reducing unit that reduces the pressure.   The pressurizing force reducing means has a driving source, and operates the driving source prior to the movement of the image carrier and the transfer device during jam processing to release the pressing force of the fixing device. 6. The image forming apparatus according to 6.

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