JP2006126750A - Laser beam printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To press a photoreceptor drum against a transfer roller in a laser beam printer with large energizing force without applying large stress to a door member and to hold it at a proper position. <P>SOLUTION: A drum energizing mechanism 30 which energizes the photoreceptor drum 2 toward the transfer roller 7 is constituted by mounting an arm member 31 having a nearly arcuate tip part 46 made to abut against a bearing part 18 of the photoreceptor drum 2 provided on a cartridge 17 and a coil spring 32 which energizes the arm member 31 on a frame member 13. When the cartridge is attached and detached, the arm member 31 is rotated following up movement of the bearing part 18 of the cartridge 17 and the cartridge 17 is smoothly attached and detached. Once the cartridge 17 is mounted on the frame member 13, the tip part 46 of the arm member 31 presses the bearing part 18 with the energizing force of the coil spring 32 and the bearing part 18 is positioned at a groove bottom position in a guide groove 37 and held. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laser beam printer having a drum urging mechanism for urging a photosensitive drum in the direction of a transfer roller.

  Conventionally, when a paper jam occurs, a laser beam printer opens a door member that is openable and closable in a printer cabinet in order to remove the recording paper jammed inside the printer. The main parts can be pulled out from the printer body. The laser beam printer has a photosensitive member so that the photosensitive drum can be properly positioned and held with respect to the transfer roller or the like when the user removes the jammed recording paper and mounts the photosensitive drum again. A drum biasing mechanism for biasing the drum is provided.

  As an example of a drum urging mechanism in a conventional laser beam printer, there is one configured to press and hold a cartridge by a cartridge that houses a photosensitive drum and a door member that is closed by a user. However, in order to accurately position the photosensitive drum during printing, it is necessary to press the photosensitive drum with a correspondingly large urging force. Therefore, in the above-described structure, the door member is closed when the door member is closed. There is a risk of damage due to large stress.

Patent Document 1 discloses a printer configured to transmit a movement of a door member by a link member connected to the door member and press the cartridge when the door member is closed. Even in such a configuration, as described above, when the door member is closed, the door member and the link member may be subjected to great stress and may be damaged.
JP-A-9-26740

  The present invention has been made to solve the above-described problems, and can press the photosensitive drum toward the transfer roller with a large urging force without applying a large stress to the door member, and can be held at an appropriate position. An object of the present invention is to provide a laser beam printer.

  In order to achieve the above object, the invention according to claim 1 is a photoconductor drum having a surface coated with a photoconductor, a charging means for uniformly charging the surface of the photoconductor drum, and a laser beam scanned on the surface of the photoconductor. An exposure unit that forms a latent image by irradiation, a developing unit that forms a toner image by attaching toner to a portion of the surface of the photoreceptor where the latent image is formed, and a photosensitive drum and a developing unit. At a predetermined transfer position downstream of the developing means in the rotational direction of the photosensitive drum, so as to face the surface of the photosensitive drum, and the surface of the recording paper is charged to charge the photosensitive drum. Transfer means for transferring the toner image formed on the surface onto the recording paper, fixing means for fixing the toner image on the recording paper by applying a predetermined heat and pressure to the recording paper on which the toner image has been transferred, and the recording paper Is loaded Out of the paper tray and the recording paper loaded in the paper feed tray, the outermost paper is transported and transported to the transfer position, the cartridge and the frame member supporting the transfer means, and the photosensitive drum are transferred. In a laser beam printer having a drum urging mechanism for urging in the direction of the roller, the cartridge has a bearing portion protruding from the frame member side for supporting the rotation shaft of the photosensitive drum, and the drum The biasing mechanism is rotatably supported by the frame member, and has an arm member having a substantially arc-shaped tip that is in contact with the bearing of the cartridge, and the arm so that the tip is in contact with the bearing. The frame member includes a pair of walls perpendicular to the rotation axis of the photosensitive drum and a frame formed parallel to the rotation axis of the photosensitive drum and continuously from the wall. A guide groove that guides the bearing portion and a winding portion of a torsion coil spring are fitted in the wall along the direction in which the cartridge is loaded, and the arm member is rotatable about the shaft. An opening for releasing one arm of the torsion coil spring is further provided, and one arm of the torsion coil spring is engaged with the flange. A spring hook is further provided, and the winding portion is fitted to the rotating shaft in a state where one arm of the torsion coil spring is released from the front opening to the side opposite to the protruding direction of the rotating shaft of the wall. Further, the arm member is rotatably supported on the rotating shaft, and the other arm of the torsion coil spring is engaged with the arm member, and then one arm is returned to the rotating shaft side from the opening to engage with the spring hook. By energizing the torsion coil spring The arm member is urged by the force in a direction in which the substantially arc-shaped tip end comes into contact with the bearing portion of the cartridge, and is removed along the guide groove to remove the recording paper jammed in the conveying means or to replace the cartridge. When attaching or detaching the cartridge, the bearing portion of the cartridge comes into contact with the substantially arc-shaped tip of the arm member, and the arm member is rotated in the direction opposite to the urging direction against the urging force of the torsion coil spring. It is possible to attach and detach the cartridge along the guide groove of the frame member without fixing the movement of the member, and the bearing portion of the photosensitive drum is properly positioned and held at the end position of the guide groove. .

  According to a second aspect of the present invention, there is provided a photosensitive drum having a photosensitive member coated on the surface thereof, a developing unit that forms a toner image on the surface of the photosensitive member, a cartridge that houses the photosensitive drum, and a surface formed on the surface of the photosensitive drum A transfer means for transferring the toner image onto the recording paper, a fixing means for fixing the toner image on the recording paper by applying predetermined heat and pressure to the recording paper on which the toner image has been transferred, and a cartridge And a door member that can be opened and closed provided in a part of the exterior cover, a frame member that supports the cartridge and the transfer means, and a drum biasing mechanism that biases the photosensitive drum in the direction of the transfer roller. In the laser beam printer, the frame member has a guide groove for guiding the cartridge along the direction in which the cartridge is loaded, and the drum urging mechanism rotates around the frame member. An arm member that is freely supported and is in contact with a part of the cartridge guided in the guide groove, and an urging unit that urges the arm member so that the arm member abuts on a part of the cartridge. The arm member is rotated by the urging force of the urging unit to press the cartridge in the direction of the transfer unit, and the photosensitive drum is positioned and held at an appropriate position.

  According to a third aspect of the present invention, in the laser beam printer according to the second aspect, when the cartridge is attached / detached along the guide groove, the bearing portion of the cartridge abuts on the substantially arc-shaped tip portion of the arm member, and the urging means By rotating the arm member in the direction opposite to the urging direction against the urging force, the cartridge can be attached to and detached from the cartridge along the guide groove of the frame member without fixing the movement of the arm member. .

  According to the first aspect of the present invention, the drum urging mechanism having the arm member and the torsion coil spring presses the photosensitive drum toward the transfer roller, so that no stress is applied to the door member provided in the printer main body. The photosensitive drum can be held at an appropriate position, and damage to the door member can be avoided. Further, since no stress is applied to the door member, it is possible to reduce the cost by reducing the thickness of the door member. When attaching or detaching the cartridge, the tip end portion of the arm member formed in a substantially arc shape comes into contact with the cartridge bearing portion, and the arm member rotates in the direction opposite to the biasing direction of the torsion coil spring. Let Thus, the user can attach and detach the cartridge only by pulling out or inserting the cartridge along the guide groove of the frame member, and the maintenance of the printer becomes easy. In addition, with one arm of the torsion coil spring released from the opening in a free state, the arm member is mounted on the rotating shaft, the other arm is engaged with the arm member, and then the one arm is engaged with the spring hook. Therefore, it is not necessary to wind the torsion coil spring when the arm member is attached to the rotating shaft. Thereby, the assembly of the drum urging mechanism can be performed easily and smoothly, and the productivity of the laser beam printer can be improved.

  According to the second aspect of the invention, the drum urging mechanism having the arm member and the urging means presses the photosensitive drum toward the transfer roller, so that no stress is applied to the door member provided in the printer main body. The photosensitive drum can be held at an appropriate position, and damage to the door member can be avoided. Further, since no stress is applied to the door member, it is possible to reduce the cost by reducing the thickness of the door member.

  According to the invention of claim 3, when the cartridge is attached or detached, the tip end portion of the arm member formed in a substantially arc shape comes into contact with the cartridge while following the part of the cartridge, and the arm member is biased by the biasing means. Therefore, the user can attach and detach the cartridge only by pulling out and inserting the cartridge along the guide groove of the frame member, and the maintenance of the printer becomes easy.

  A laser beam printer according to the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows a configuration example of the laser beam printer 1. The laser beam printer 1 includes a photosensitive drum 2 having a photosensitive member coated on the surface thereof, a cleaner 3 sequentially disposed around the photosensitive drum 2 from the upstream side to the downstream side in the rotation direction A, and a charger. (Charging unit) 4, laser exposure device (exposure unit) 5, developing brush (developing unit) 6, transfer roller (transfer unit) 7, and downstream of the transfer roller 7 in the conveyance direction B of the recording paper P An arranged fixing roller (fixing means) 8, a paper feed tray 9 loaded with recording paper P, a paper discharge tray 10 on which printed recording paper P is deposited, and a recording paper P for conveying A recording paper transport mechanism (transport means) 11 and the like are included. Each of the above components is attached to the frame member 13. The frame member 13 is provided with a cabinet 14 that covers each of the above components and forms the exterior of the laser beam printer 1. The upper portion of the frame member 13 is used to remove the recording paper P jammed in the recording paper transport mechanism 11. A door member 15 for replacing a later-described cartridge 17 is provided so as to be freely opened and closed.

  The cleaner 3 removes toner and paper dust before one stroke (one rotation) adhering to the surface of the photosensitive drum 2 and cleans the drum surface. The charger 4 uniformly charges the surface of the photosensitive drum 2 cleaned by the cleaner 3. The laser exposure device 5 has a laser diode as a light source, and forms a latent image by irradiating the surface of the photosensitive drum 2 charged by the charger 4 while scanning the laser beam L. The laser exposure device 5 is supplied with power by a power supply device (not shown), and a light emission voltage for light emission of the laser diode is applied. The developing brush 6 forms a toner image by attaching toner to a portion of the surface of the photosensitive drum 2 where the latent image is formed. The transfer roller 7 is provided so as to oppose the surface of the photosensitive drum 2, and charges the surface of the recording paper P while pressing the recording paper P against the surface of the photosensitive drum 2. The formed toner image is transferred onto the recording paper P. A transfer voltage for charging the surface of the recording paper P is applied to the transfer roller 7 from a power supply device. The fixing roller 8 sandwiches the recording paper P together with the rollers 18 arranged at opposite positions, and applies heat and pressure to the recording paper P to fix the toner. Heat for fixing the toner is supplied from a heater (for example, a halogen lamp) built in the fixing roller 8. A fixing voltage generated by a power supply device is applied to the heater.

  The recording paper transport mechanism 11 includes a pickup roller 11a, transport rollers 11b, 11c, and 11d, a paper stacking plate 20 that is disposed in the vicinity of the paper feed tray 9, and presses the loaded recording paper P against the pickup roller 11a. A coil spring 21 or the like for urging the paper stacking plate 20 toward the pickup roller 11a is provided.

  A recording paper placement surface 23 on which the recording paper P is placed is continuously formed by the paper feed tray 9 and the paper stacking plate 20. When the user inserts a plurality of recording papers P in a stacked state from the side of the paper feed tray 9, the recording papers P are placed on the recording paper placement surface 23.

  The pickup roller 11a is disposed to face the recording paper placement surface 23, and sends the outermost recording paper P placed on the recording paper placement surface 23 to the transport roller 11b. The transport roller 11b sends the recording paper P sent out by the pickup roller 11a to the transport roller 11c. The transport rollers 11c and 11d are arranged so as to face each other between the transport roller 11b and the transfer roller 7, and transport the recording paper P sent out by the transport roller 11b to the transfer position.

  The photosensitive drum 2 and the developing brush 6 are mounted on a cartridge 17 that houses a toner tank 12 filled with toner. Therefore, when the user replaces the photosensitive drum 2 or the toner tank 12 which is a consumable item, the door member 15 is opened, the cartridge 17 is pulled out from the main body of the laser beam printer 1, and then each part is replaced. . When both the photosensitive drum 2 and the toner tank 12 are consumed, the cartridge 17 may be replaced with a new one. When the recording paper P is jammed by the recording paper transport mechanism 11 around the photosensitive drum 2, the door member 15 is opened and the cartridge 17 is removed from the main body of the laser beam printer 1 as described above. The recording paper P can be easily removed.

  2 and 3 show a cartridge 17 supported by the frame member 13 and a drum urging mechanism which is disposed in the vicinity of the end of the cartridge 17 and urges the photosensitive drum 2 in the direction of the transfer roller 7 (arrow C direction). 30 configurations are shown. The photosensitive drum 2 is urged in the direction of the transfer roller 7 by the drum urging mechanism 30 via the bearing portion 18. The drum biasing mechanism 30 includes an arm member 31 that presses the photosensitive drum 2 toward the transfer roller 7 and a torsion coil spring 32 that biases the arm member 31. The arm member 31 is rotatably supported on a rotating shaft 33 (see FIG. 4) provided on the frame member 13, and the torsion coil spring 32 has a winding portion 34 attached to the rotating shaft 33. Yes.

  The frame member 13 is disposed so as to face the end surface of the cartridge 17, and is formed so as to be continuous and substantially orthogonal to a pair of walls 35 (only one is shown in FIG. 3) that supports the cartridge 17 from both ends. The flange 36 is provided. The wall 35 is formed substantially perpendicular to the rotation shaft 33 of the photosensitive drum 2, and the flange 36 is formed substantially parallel to the rotation shaft 33. A guide groove 37 for guiding the bearing portion 18 formed in the cartridge 17 and a winding portion 34 of the torsion coil spring 32 are fitted on the wall 35 along the direction in which the cartridge 17 is loaded, and the arm A rotation shaft 33 (see FIG. 4) for pivotally supporting the member 31, a stopper 38 for restricting the rotatable range of the arm member 31, and one arm 39 of the torsion coil spring 32 for escaping. An opening 40 is provided. The flange 36 is provided with a spring hook 41 with which one arm 39 of the torsion coil spring 32 is engaged.

  The cartridge 17 has a bearing portion 18 for supporting the rotating shaft 16 of the photosensitive drum 2 at both ends thereof. The bearing portion 18 protrudes from the end surface of the cartridge 17 toward the wall 35 of the frame member 13 and is guided by the guide groove 37 of the frame member 13.

  The arm member 31 and the torsion coil spring 32 are attached to the walls 35 of the frame member 13 on both ends or one end of the cartridge 17. The arm member 31 includes a hole 45 (see FIG. 4) into which the rotation shaft 33 of the frame member 13 is inserted, a substantially arcuate tip 46 that contacts the bearing 18 of the cartridge 17, and a torsion coil spring 32. The other arm 42 has a spring abutting portion 47 against which the other arm 42 abuts. The spring contact portion 47 is provided between the hole 45 and the tip portion 46. In the torsion coil spring 32, one arm 39 extended from a winding portion 34 attached to the rotation shaft 33 is engaged with a spring hook 41 of the flange 36, and the other arm 42 is a spring contact of the arm member 31. The arm member 31 is abutted against the contact portion 47 and urges the arm member 31 in the direction in which the tip end portion 46 of the arm member 31 abuts on the bearing portion 18, that is, the arrow C direction.

  Next, the assembly process of the drum urging mechanism 30 in the manufacturing process of the laser beam printer 1 will be described with reference to FIGS. 4 and 5. First, from the state shown in FIG. 4 (a), one arm 39 of the torsion coil spring 32 is inserted through the opening 40 on the opposite side to the protruding direction of the rotation shaft 33 of the wall 35 and escaped. 34 is fitted to the rotation shaft 33. Thereby, the torsion coil spring 32 is attached to the rotating shaft 33 as shown in FIG. Then, the other arm 42 is engaged with the spring contact portion 47 of the arm member 31 while the one arm 39 of the torsion coil spring 32 is in a free state (not engaged with the spring hook 41). Further, after aligning the hole 45 of the arm member 31 with the rotation shaft 33, the arm member 31 is pushed toward the wall 35. At this time, since one arm 39 of the torsion coil spring 32 is in a free state, the urging force by the torsion coil spring 32 is not generated, and the operator is not bothered by the urging force by the torsion coil spring 32. Can be incorporated into the rotary shaft 33. Depending on the shape of the opening 40, one arm 39 of the torsion coil spring 32 is lightly engaged with the edge of the opening 40. However, since the urging force generated thereby is very small, Not so much as to affect. Thereafter, when the screw 50 is screwed into the screw hole 51 provided at the tip of the rotation shaft 33, the mounting of the arm member 31 is completed as shown in FIG.

  FIG. 5D shows a state where the arm member 31 and the torsion coil spring 32 are mounted on the rotation shaft 33 from the side where the cartridge 17 is mounted. After the arm member 31 is mounted, one arm 39 of the torsion coil spring 32 is moved along the arrow D while returning to the side where the rotation shaft 33 is located from the opening 40, as shown in FIG. 5 (e). By engaging with the spring hook 41, a biasing force of the torsion coil spring 32 is generated, and the arm member 31 is biased in the direction of arrow C.

  Incidentally, in the drum urging mechanism 30 applied to the present embodiment, when the positioning of the photosensitive drum 2 is accurately performed during printing, the photosensitive drum 2 is moved to the side of the transfer roller 7 with a correspondingly large urging force. Therefore, the torsion coil spring 32 having a relatively large spring constant is used. Therefore, in the step of engaging one arm 39 of the torsion coil spring 32 with the spring hook 41 from FIG. 5D to FIG. 5E, the torsion coil spring 32 is wound with a large force against the urging force. It needs to be tightened. However, in this embodiment, as shown in FIG. 4C, since the mounting of the arm member 31 to the rotating shaft 33 has already been completed, the operator can adjust the position of the arm member 31. It is possible to concentrate on the work of engaging the arm 39 with the spring hook 41 without paying attention to the engagement state of the arm 42 and the spring contact portion, and the assembly work of the drum urging mechanism 30 becomes easy.

  2 and 3, when the cartridge 17 is pulled out along the guide groove 37 by the user in order to remove the recording paper P jammed in the recording paper transport mechanism 11 or replace the cartridge 17, The arm member 31 is rotated in the direction opposite to the arrow C direction following the movement of the bearing portion 18. As a result, the contact between the bearing portion 18 of the cartridge 17 and the distal end portion 46 of the arm member 31 is released, and the cartridge 17 can be removed. At this time, the arm member 31 released from contact with the bearing portion 18 of the cartridge 17 is rotated in the direction of arrow C by the urging force of the torsion coil spring 32, but the stopper protruding from the wall 35 is provided. 38, the rotatable range of the arm member 31 is restricted, and the distal end portion 46 is held at a position overlapping the guide groove 37 in a side view.

  On the other hand, when the cartridge 17 is reinserted along the guide groove 37, the tip end portion 46 held at the above-described position contacts the bearing portion 18 of the cartridge 17, and the arm member 31 moves the bearing portion 18. Is rotated in the direction opposite to the arrow C direction. When the bearing portion 18 is positioned closer to the groove bottom side of the guide groove 37 than the distal end portion 46 of the arm member 31, the bearing portion 18 is directed toward the groove bottom of the guide groove 37 by the substantially arc-shaped distal end portion 46. Thus, the bearing portion 18 of the cartridge 17 is positioned and held at an appropriate position in contact with the groove bottom of the guide groove 37. In this way, the user can attach and detach the cartridge 17 only by pulling out or inserting the cartridge 17 along the guide groove 37 of the frame member 13.

  As described above, according to the laser beam printer 1 of the present embodiment, the photosensitive drum 2 is pressed against the transfer roller 7 by the drum biasing mechanism 30 having the arm member 31 and the torsion coil spring 32. The photosensitive drum 2 can be held at an appropriate position without applying stress to the door member 15 provided in the main body of the printer 1, and damage to the door member 15 can be avoided. Further, since no stress is applied to the door member 15, it is possible to reduce the cost by reducing the thickness of the door member 15. Further, when the cartridge 17 is attached or detached, the tip end portion 46 of the arm member 31 formed in a substantially arc shape comes into contact with the bearing portion 18 of the cartridge 17 so that the arm member 31 faces in the direction opposite to the arrow C direction. Rotate to Thus, the user can attach and detach the cartridge 17 simply by pulling out or inserting the cartridge 17 along the guide groove 37 of the frame member 13, and the laser beam printer 1 can be easily maintained. Further, the arm member 31 is mounted on the rotating shaft 33 in a free state in which one arm 39 of the torsion coil spring 32 is released from the opening 40, and the other arm 42 is engaged with the spring contact portion 47 of the arm member 31. After that, since the one arm 39 is engaged with the spring hook 41, it is not necessary to wind the torsion coil spring 32 when the arm member 31 is attached to the rotating shaft 33. As a result, the drum urging mechanism 30 can be assembled easily and smoothly, and the productivity of the laser beam printer 1 can be increased.

  The present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible. For example, the cartridge is not limited to the configuration that accommodates the photosensitive drum 2, the developing brush 6, and the toner tank 12. Alternatively, only the photosensitive drum 2 may be accommodated. In this case, the developing brush 6 may be supported by the frame member 13 and the toner tank 12 may be accommodated in a separately provided toner cartridge. Of the frame member 13, the wall 35 and the flange 36 are separate subframes that are additionally mounted to support the cartridge 17 and the like with respect to the main frame forming the skeleton of the laser beam printer 1. It may be configured. The member that biases the arm member 31 is not limited to the torsion coil spring 32, and other spring members or elastic members such as rubber members may be applied.

The figure which shows the structure of the laser beam printer by one Embodiment of this invention. The side view which shows the structure of the cartridge with which the flame | frame was mounted | worn, and the drum urging | biasing mechanism. Perspective view of the cartridge and drum urging mechanism The perspective view which shows the first half process of an assembly of a drum urging | biasing mechanism from the arm member side. The perspective view which shows the assembly process latter half process of the drum energizing mechanism from the side in which a cartridge is mounted | worn.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser beam printer 2 Photosensitive drum 4 Charger (charging means)
5 Laser exposure equipment (exposure means)
6 Developing brush (Developing means)
7 Transfer roller (transfer means)
8 Fixing roller (fixing means)
9 Paper feed tray 11 Recording paper transport mechanism (transport means)
13 Frame member 16 Rotating shaft 17 Cartridge 18 Bearing portion 30 Drum biasing mechanism 31 Arm member 32 Torsion coil spring 33 Rotating shaft 34 Winding portion 35 Wall 36 Flange 37 Guide groove 38 Stopper 40 Opening 41 Spring hook 46 Tip portion

Claims (3)

A photoreceptor drum having a photoreceptor coated on the surface;
Charging means for uniformly charging the surface of the photosensitive drum;
Exposure means for forming a latent image by irradiating the surface of the photoconductor while scanning with a laser beam;
Developing means for forming a toner image by attaching toner to a portion of the surface of the photoreceptor where a latent image is formed;
A cartridge containing the photosensitive drum and developing means;
At a predetermined transfer position downstream of the developing means in the rotational direction of the photosensitive drum, the photosensitive drum is provided to face the surface of the photosensitive drum, and the surface of the recording paper is charged to Transfer means for transferring the toner image formed on the surface onto the recording paper;
Fixing means for applying a predetermined heat and pressure to the recording paper on which the toner image has been transferred to fix the toner image on the recording paper;
A paper tray loaded with recording paper,
Out of the recording paper loaded in the paper feed tray, the outermost one is transported and transported to the transfer position;
A frame member for supporting the cartridge and the transfer means;
In a laser beam printer comprising a drum biasing mechanism for biasing the photosensitive drum in the direction of the transfer roller,
The cartridge has a bearing portion protruding on the frame member side for supporting the rotating shaft of the photosensitive drum,
The drum urging mechanism is rotatably supported by the frame member, and has an arm member having a substantially arcuate tip portion that comes into contact with the bearing portion of the cartridge, and the tip portion comes into contact with the bearing portion. A torsion coil spring for urging the arm member,
The frame member has a pair of walls perpendicular to the rotation axis of the photosensitive drum and a flange formed in parallel with the rotation axis of the photosensitive drum and continuously from the wall,
A guide groove that guides the bearing portion and a winding portion of the torsion coil spring are fitted on the wall along the direction in which the cartridge is loaded, and the arm member is rotatable about the shaft. A pivot shaft to be supported; a stopper for restricting the rotatable range of the arm member; and an opening for releasing one arm of the torsion coil spring;
The flange is further provided with a spring hook to which one arm of the torsion coil spring is engaged,
The winding portion is fitted to the rotating shaft in a state where one arm of the torsion coil spring is escaped from the front opening to the opposite side of the protruding direction of the rotating shaft of the wall, and the arm member is further mounted on the rotating shaft. After pivotally supporting the rotating shaft and engaging the other arm of the torsion coil spring with the arm member, the one arm is returned to the rotating shaft side from the opening, and the spring hook and By engaging, the arm member is urged by the urging force of the torsion coil spring in a direction in which the substantially arcuate tip portion contacts the bearing portion of the cartridge,
When removing or inserting the cartridge along the guide groove in order to remove the recording paper jammed in the conveying means or to replace the cartridge, the bearing portion of the cartridge is a substantially arcuate tip portion of the arm member. The arm member is rotated against the urging force of the torsion coil spring against the urging force of the torsion coil spring and rotated along the guide groove of the frame member without fixing the movement of the arm member. The laser beam printer is characterized in that it can be attached to and detached from the cartridge, and the bearing portion of the photosensitive drum is appropriately positioned and held at the end position of the guide groove. A photoreceptor drum having a photoreceptor coated on the surface;
Developing means for forming a toner image on the surface of the photoreceptor;
A cartridge containing the photosensitive drum;
Transfer means for transferring a toner image formed on the surface of the photosensitive drum onto a recording paper;
Fixing means for applying a predetermined heat and pressure to the recording paper on which the toner image has been transferred to fix the toner image on the recording paper;
An openable and closable door member provided in a part of the exterior cover for attaching and detaching the cartridge;
A frame member for supporting the cartridge and the transfer means;
In a laser beam printer comprising a drum biasing mechanism for biasing the photosensitive drum in the direction of the transfer roller,
The frame member has a guide groove for guiding the cartridge along a direction in which the cartridge is loaded;
The drum urging mechanism is rotatably supported by the frame member and is in contact with a part of the cartridge guided by the guide groove, and the arm member is in contact with a part of the cartridge. A biasing means for biasing the arm member,
The laser beam is characterized in that the arm member is rotated by the urging force of the urging unit to press the cartridge in the direction of the transfer unit, and the photosensitive drum is positioned and held at an appropriate position. Printer.   When attaching and detaching the cartridge along the guide groove, the bearing portion of the cartridge abuts on a substantially arcuate tip portion of the arm member, and the arm member is biased in the biasing direction against the biasing force of the biasing means. 3. The laser according to claim 2, wherein the cartridge can be attached to and detached from the cartridge along the guide groove of the frame member without fixing the movement of the arm member by rotating in the opposite direction. Beam printer.

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