JP2019148787A - Locking mechanism and image forming device - Google Patents

Abstract

To provide a locking mechanism which reduces temperature rise and power consumption and has a space-saving configuration.SOLUTION: Provided is a locking mechanism which allows a plunger to be held at a first position by making a pressing force of a spring member greater than a magnetic force of a magnet in an unexcited state, and allows the plunger to be held at a second position by making the pressing force of the spring member less than the magnetic force of the magnet in the unexcited state.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a lock mechanism that locks an object and an image forming apparatus.

  In image forming apparatuses such as laser printers, ink jet printers, and copiers, it is common for a user to replace consumables such as cartridges at a predetermined timing. On the other hand, depending on the company, it may be desirable to be able to control replacement of consumables such as cartridges in an office environment where the image forming apparatus is used.

  As means for controlling replacement of consumables, there is means for providing a lock mechanism on a door that opens and closes in order to replace consumables. During normal use, the door is locked, and the lock is released only when the user performs a specific operation from the control panel, so that the consumable can be replaced (Patent Document 1). Then, after the apparatus main body recognizes that the user has exchanged for a new consumable, the lock mechanism is operated to lock the door. As a specific lock mechanism, a lock configuration in which a lock lever having a lock claw is driven by a plunger type solenoid to lock an open / close door is generally used (Patent Document 2). On the other hand, the consumable item is not always replaced immediately after the lock is released, but may be left as it is depending on the user. In such a situation, the plunger type solenoid is energized for a long time, which is not preferable from the viewpoint of temperature rise and power consumption.

  As means for solving this, a configuration in which a plunger type solenoid and a holding type solenoid are used in combination has been proposed (Patent Document 3). The plunger solenoid is energized and operated only when the lock lever having the lock claw is unlocked. In the unlocked position, the lock lever is held only by the force of the magnet built in the holding solenoid. The plunger of the plunger type solenoid tries to return to the original position, but the lock lever is held at a position where the magnetic force of the magnet of the holding solenoid is large and the lock is released. When locking again, the holding solenoid is energized to generate an electromagnetic force in a direction opposite to the direction of attractive force by the magnetic force to return the lock lever to the locked state.

US Pat. No. 6,768,877 JP-A-8-2794 Japanese Patent No. 4842866

  By the way, in the lock mechanism of patent document 3, although temperature rise and electric power consumption can be reduced, since the space which arrange | positions at least 2 or more solenoid is required, a lock mechanism will enlarge. In addition, the cost increases accordingly.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lock mechanism and an image forming apparatus having a space-saving configuration while reducing temperature rise and power consumption.

  The present invention provides a lock mechanism and an image forming apparatus described in the claims.

  Further, the present invention is a lock mechanism, which can hold the plunger at the first position when the biasing force of the biasing member is larger than the magnetic force of the magnet in the non-excited state, and biases the biasing member in the non-excited state. A locking mechanism that can hold the plunger in the second position because the force is smaller than the magnetic force of the magnet is provided.

  According to the present invention, it is possible to provide a lock mechanism and an image forming apparatus having a space-saving configuration while reducing temperature rise and power consumption.

Cross-sectional explanatory drawing showing the configuration of the image forming apparatus The perspective view which shows the structure of the image forming apparatus provided with the locking mechanism. The perspective view of the lock unit simple substance of Example 1 Sectional drawing at the time of a lock | rock in the state with which the lock unit of Example 1 was mounted | worn with the apparatus main body of the image forming apparatus Sectional drawing at the time of unlocking | release in the state with which the lock unit of Example 1 was mounted | worn with the apparatus main body of the image forming apparatus Illustration of holding solenoid Detailed explanatory view of the internal parts of the lock unit of the first embodiment Explanatory drawing showing the relationship between holding solenoid and spring force Detailed explanatory drawing of the lock lever claw part of Example 1 Cross-sectional explanatory drawing of manual unlocking of Example 1 The perspective view of the lock unit simple substance of Example 3 Sectional drawing in the state with which the lock unit of Example 3 was mounted | worn with the apparatus main body of the image forming apparatus Detailed explanatory drawing of lock lever claw part of Example 3 Sectional drawing at the time of a lock | rock in the state with which the lock unit of Example 4 was mounted | worn with the apparatus main body of the image forming apparatus Sectional drawing at the time of unlocking | release in the state with which the lock unit of Example 4 was mounted | worn with the apparatus main body of the image forming apparatus Explanatory drawing which showed the modification of Example 1. Detailed explanatory view of the inside of the cartridge door of Example 1 Explanatory drawing which showed the decomposition | disassembly state of the cartridge door of Example 1 Explanatory drawing which showed the relationship between the cartridge door with a shield board of Example 1, and a lock unit. Explanatory drawing which showed the lock unit periphery of Example 2 with a cover state Explanatory drawing which showed the lock unit periphery of Example 2 in the state without a cover Explanatory drawing which showed the lock lever and shield board of Example 2. Explanatory drawing which the lock unit of Example 2 showed the lock position state Explanatory drawing which the lock unit of Example 2 showed the lock release position state

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments.

(Overall configuration of image forming apparatus)
The overall configuration of the image forming apparatus will be described. The image forming apparatus will be described using an electrophotographic color laser printer, but is not limited thereto. For example, a monochrome laser printer may be used.

  The color image forming apparatus shown in FIG. 1 includes four process cartridges 7a, 7b, 7c, and 7d that can be attached to and detached from the apparatus main body A of the image forming apparatus. These four process cartridges 7a, 7b, 7c, and 7d have the same structure, but contain toners of different colors, that is, yellow (Y), magenta (M), cyan (C), and black (Bk). Yes. Therefore, each process cartridge is different in that an image is formed with a different color. The process cartridges 7a, 7b, 7c and 7d are constituted by developing units 4a, 4b, 4c and 4d and toner units 5a, 5b, 5c and 5d. Of these, the former developing units 4a, 4b, 4c, and 4d have photosensitive drums 1a, 1b, 1c, and 1d, which are image carriers, and charging rollers 2a, 2b, 2c, and 2d, respectively. The developing units 4a, 4b, 4c, and 4d have drum cleaning blades 8a, 8b, 8c, and 8d and waste toner containers 6a, 6b, 6c, and 6d. Further, the developing units 4a, 4b, 4c, and 4d include developing rollers 40a, 40b, 40c, and 40d, and developer application rollers 41a, 41b, 41c, and 41d.

  A scanner unit 3 is disposed above the process cartridges 7a, 7b, 7c, and 7d, and performs exposure based on image signals to the photosensitive drums 1a, 1b, 1c, and 1d.

  The photosensitive drums 1a, 1b, 1c, and 1d are charged to a predetermined negative potential by the charging rollers 2a, 2b, 2c, and 2d, and then electrostatic latent images are formed by the scanner unit 3, respectively. The electrostatic latent image is reversely developed by the developing units 4a, 4b, 4c, and 4d, and negative toner is adhered. Then, the electrostatic latent image is developed to form Y, M, C, and Bk toner images, respectively.

  In the intermediate transfer belt unit 112, an intermediate transfer belt 112e is stretched around a driving roller 112f, a secondary transfer counter roller 112g, and a tension roller 112h, and the tension roller 112h applies tension in the direction of arrow n. Further, primary transfer rollers 112a, 112b, 112c, and 112d are disposed inside the intermediate transfer belt 112e so as to face the photosensitive drums 1a, 1b, 1c, and 1d, and a transfer bias is applied by a bias applying unit. It has a configuration.

  The toner images formed on the photosensitive drums 1a, 1b, 1c, and 1d are primarily transferred onto the intermediate transfer belt 112e and conveyed to the secondary transfer unit 115 in a state where the four color toner images are overlapped. Here, each photosensitive drum rotates in the arrow S direction, and the intermediate transfer belt 112e rotates in the arrow R direction. A positive bias is applied to the primary transfer rollers 112a, 112b, 112c, and 112d, and the toner images are primarily transferred onto the intermediate transfer belt 112e sequentially from the toner image on the photosensitive drum 1a to the toner image on the photosensitive drum 1d. The

  The feeding / conveying device 113 includes a paper feed roller 9 that feeds the transfer material S from the paper feed cassette 111 that stores a transfer material (recording material) S such as paper, and a transport roller that transports the fed transfer material S. 10. Then, the transfer material S conveyed from the feeding / conveying device 113 is conveyed to the secondary transfer unit 115 by the registration roller pair 117.

  In the secondary transfer unit 115, a four-color toner image on the intermediate transfer belt 112 is secondarily transferred to the transferred transfer material S by applying a positive bias to the secondary transfer roller 116.

  After the toner image is transferred, the transfer material S is conveyed to the fixing device 114, and is heated and pressed by the fixing roller 96a and the pressure roller 96b to fix the toner image on the surface of the transfer material S. The fixed transfer material P is discharged to the paper discharge tray 121 by the paper discharge roller pair 120.

  In the case of duplex printing, after the transfer material S is fixed to the fixing device 114, the double-sided flapper 181 swings downward, the transfer material S is guided to the reverse conveyance path, and the conveyance direction is reversed by the reverse roller 180. The transfer material S reversely conveyed by the reverse roller 180 is conveyed in the double-sided conveyance path, conveyed by the double-sided conveyance roller 182, and again conveyed to the transfer unit 115 and the fixing device 114, and the toner image is fixed on the back surface. The paper is discharged to the paper discharge tray 121.

(Explanation of lock mechanism and lock operation)
In the lock unit, which is the lock mechanism of this embodiment, a lock unit 202 and a lock unit 203 are arranged at two positions on the left and right inside the main body of the printer 201 which is the image forming apparatus shown in FIG. A door 205 (hereinafter referred to as a cartridge door) that is an opening / closing member that opens and closes when the cartridge 204 is replaced is provided on the front surface of the printer 201. In this embodiment, when the cartridge is exposed and visible from the outside of the image forming apparatus, the position where the cartridge door as the opening / closing member is positioned is set as the first opening position. Further, when the cartridge is covered and cannot be seen from the outside of the image forming apparatus, the position where the cartridge door as the opening / closing member is positioned is set as the second closed position.

  The cartridge door 205, which is an opening / closing member, is provided with two latches 205a, one at a location corresponding to each lock unit (the lock unit 202 and the lock unit 203).

  FIG. 3 shows a lock unit 300 which is a lock mechanism of the present embodiment. The lock unit 300 includes a holding solenoid 301 containing a permanent magnet, a lock lever 302 that is a lock member, and a rotation shaft 303 of the lock lever. The lock unit 300 includes a pin 304 for connecting (engaging) the plunger 601 of the holding solenoid 301 and the lock lever 302 as a lock member, and a lock holder 305 made of sheet metal. Furthermore, the lock unit 300 includes a screw 306 that fastens the lock holder 305 and the holding solenoid 301, a spring 307 that biases the lock lever 302, and an E-ring 308 that stops the lock lever shaft.

  FIG. 4 shows a state where the lock unit is attached to the main body of the image forming apparatus. In the lock unit 300, the hook portion 305 a of the lock holder 305 is hooked on the apparatus main body frame 401 of the image forming apparatus, and the other bent portion (not shown) is fixed with a screw 402. By providing the rotation shaft 303 of the lock lever in the vicinity of the hook portion 305a of the lock holder, the force transmission is substantially in a straight line as shown by the dotted arrow in FIG. Therefore, the opening force of the cartridge door received by the lock lever 302 from the latch portion 205a can be received by the hook portion 305a of the lock holder 305 via the lock lever 302, and can withstand a large force.

  The surface 302a of the lock claw 302c of the lock lever 302 is held at a position where it is locked to the latch portion 205a of the cartridge door. Therefore, even if the cartridge door 205 is to be opened in the P direction, the surface 302a of the lock claw 302c and the latch portion 205a come into contact with each other and the cartridge door 205 is not opened any more.

  FIG. 5 shows a state where the lock unit 300 is unlocked. Since the lock lever 302 rotates to the position where the surface 302a of the lock claw 302c is retracted from the latch portion 205a, the cartridge door 205 can be freely opened and closed.

  Next, the timing when the lock unit operates will be described. During normal use, the cartridge door is locked and cannot be opened. When the remaining amount of toner in the cartridge is low and the predetermined replacement timing is reached, the printer automatically unlocks and informs the user that it is time to replace the cartridge. The user opens the cartridge door, replaces the cartridge with a new one, closes the cartridge door, recognizes that the printer has been replaced with a new cartridge, and automatically returns to the locked state.

  In this embodiment, the cartridge is automatically unlocked when the amount of toner remaining in the cartridge is low. However, the user can control the replacement of consumables such as a cartridge by unlocking after entering a predetermined code through the control panel. Any specification that can be used.

(Force relationship in the lock mechanism)
The relationship of the locking mechanism force will be described. In the lock mechanism of this embodiment, the plunger of the holding solenoid is movable between the lock position (first position) and the lock release position (second position). The direction from the second position to the first position is the first direction, and the direction from the first position to the second position is the second direction. That is, the direction opposite to the first direction is the second direction. In this embodiment, the lock position is the first position and the lock release position is the second position, but this relationship may be reversed. That is, the lock position is the second position, and the lock release position is the first position.

  Hereinafter, the relationship between the forces at the two positions of the lock position (first position) and the lock release position (second position) in the non-energized state (non-excited state) will be described. First, the holding solenoid will be described with reference to FIG. The holding solenoid 301 has a coil 301b, and the coil 301b can be energized in both directions. As shown in FIG. 6A, when a current flows in the first current direction, an electromagnetic force is generated in a direction in which the plunger 601 is pulled into the holding solenoid 301 from the coil 301b. For this reason, the plunger 601 moves in the second direction and moves to the second position in the holding solenoid 301.

  On the other hand, as shown in FIG. 6B, when a current flows in a direction opposite to the first current direction (second current direction), an electromagnetic force is generated in a direction in which the plunger 601 is pushed out from the coil. For this reason, the plunger 601 moves in the first direction and moves to the first position protruding outward from the holding solenoid 301.

  The holding solenoid has a built-in permanent magnet 301c, and in a non-energized state (non-excited state), a force is always applied in the direction in which the plunger is pulled (second direction) by the magnetic force of the permanent magnet 301c. For this reason, the plunger 601 cannot be held in the state of FIG. 6B in the first position only by the holding solenoid. Therefore, in this embodiment, a spring that is a biasing member is used to hold the plunger 601 in the state of FIG. 6B in the first position.

  FIG. 7 shows an attached state of a spring which is an urging member. The spring 307 of the present embodiment is a torsion spring, the fixed end 307 a is fixed to the lock holder 305, and the free end 307 b is fixed to the lock lever 302. The lock lever is biased in the locking direction by the spring force of the spring as the biasing member. When the spring force in the first direction is stronger than the magnetic force in the second direction by the magnet of the holding solenoid 301, the plunger 601 can be held in the locked state at the first position, which is the locked position, in a non-energized state (non-excited state).

  In order to perform all operations with only one holding solenoid and one spring, it is necessary that the lock lever can be operated in the energized state and that the lock lever can be held in two positions in the non-energized state. For that purpose, it is necessary to set the spring pressure F of the spring as follows.

  The force relationship is shown in FIG. In order to explain only the relationship of force, illustrations such as a lock lever and a spring are omitted, and only the force acting on the plunger of the holding solenoid is indicated by an arrow. In FIG. 8, it is assumed that the lock lever is in the lock position when the plunger 601 is in the first position and the lock lever is in the lock release position when the plunger 601 is in the second position.

  Each force is defined as follows. First, let F be a biasing force that biases the lock lever, which is the lock member, in the lock direction, which is the first direction, by the spring, which is the bias member. Let M be the permanent magnet attractive force in the second direction by the magnet of the holding solenoid. Let E be the coil attractive force generated from the coil by energization in the first current direction in order to move the plunger of the holding solenoid in the first direction. In order to move the plunger of the holding solenoid in the second direction, let R be the restoring force generated from the coil when energized in the direction opposite to the first current direction (second current direction).

  Further, when the plunger is in the first position (the locked state where the lock member locks the cartridge door), the biasing force in the first direction that biases the lock lever that is the lock member by the spring that is the bias member is F1. . When the plunger is in the second position (the unlocked state in which the lock between the lock member and the cartridge door is released), the biasing force in the first direction that biases the lock lever that is the lock member by the spring that is the biasing member is applied. Let it be F2. The permanent magnet attractive force in the second direction in which the magnet acts on the plunger when the plunger is in the first position is M1, and the permanent magnet in the second direction in which the magnet when the plunger is in the second position acts on the plunger. The suction force is M2.

In this case, it is necessary to satisfy the following conditions 2 and 4.
Condition 1 F1 <M1 + E
Condition 2 F2 <M2
Condition 3 F2 + R> M2
Condition 4 F1> M1
That is, the condition 2 is a condition for holding the plunger in the second position without being excited when the plunger is in the second position. Condition 4 is a condition for holding the plunger in the first position without excitation when the plunger is in the first position.

  By satisfying this condition, the plunger can be held in a non-energized state (non-excited state) even when the plunger is positioned at the first position or the second position.

  Conditions 1 and 3 are conditions under which the plunger can move in an energized state (excited state). In the present invention, it is important to hold the plunger in a non-excited state, and a configuration for realizing it is disclosed, and it is sufficient that at least the conditions 2 and 4 are satisfied.

  Further, each condition will be described.

  Condition 1 is a condition for transitioning from a locked state in which the lock lever, which is a locking member, locks the cartridge door, which is an opening / closing member, to an unlocked state in which the cartridge door is unlocked. At this time, a current flows in the coil of the holding solenoid in the first current direction to generate a coil attractive force E in the second direction, and the sum of the permanent magnet attractive force M1 of the magnet in the same direction as the second direction is The state can be changed by becoming larger than the urging force F1 in one direction.

  Condition 2 is a condition in which the lock lever, which is a lock member, is held in a non-energized (non-excited) state in the unlocked state in which the lock with the cartridge door is released. In this embodiment, the plunger of the holding solenoid is held in the second position. In the unlocked state, the plunger tip 601a hits the main body bottom 301a of the holding solenoid and is close to a permanent magnet, so that a strong magnetic force is generated. For this reason, the permanent magnet attractive force M2 is larger than the permanent magnet attractive force M1. When the force of the biasing force F2 in the first direction of the spring, which is the biasing member, is smaller than the force of the permanent magnet attracting force M2 in the second direction, the plunger is in the second position where it hits the main body bottom 301a of the holding solenoid. It is possible to maintain the state in the unlocked state. In this embodiment, the state in which the plunger abuts against the main body bottom portion 301a of the holding solenoid is the second position of the plunger, but the present invention is not limited to this.

  Condition 3 is a condition in which the lock lever that is the lock member makes a transition from the unlocked state to the locked state that locks the opening / closing member. At this time, a coil restoring force R in the first direction due to energization in the second current direction is generated in the coil of the holding solenoid, and the sum of the biasing force F2 in the same direction as the first direction is the permanent magnet attracting force in the second direction. State transition becomes possible by becoming larger than force M2.

  Condition 4 is a condition in which the lock lever, which is a lock member, maintains the state without energization (non-excitation) in the locked state in which the opening / closing member is locked. At this time, since the urging force F1 in the first direction is larger than the permanent magnet attractive force M1 in the second direction, the state in the locked state can be maintained. Condition 4 in the present embodiment is a state where the plunger is in the first position and the state is maintained.

  In the above, the state in which the plunger is retracted holds the state by magnetic force (condition 2), and the state in which the plunger is pushed out is maintained by the spring force (condition 4). No.

  For example, as shown in FIG. 16, the main body bottom portion 301a does not exist in the holding solenoid body, and the plunger is held with the plunger after the plunger has moved to the first position in the state where the plunger tip 601a does not hit the second position so far. A configuration in which the solenoid body abuts may be used. As shown in FIG. 16, the state in which the plunger is retracted (condition 2) is held by a spring force, and the state in which the plunger is pushed out (condition 4) is held by a magnetic force.

In this case, the following force relationship is obtained.
Condition 1 F1 + E> M1
Condition 2 F2> M2
Condition 3 F2 <M2 + R
Condition 4 F1 <M1
Here, each force becomes the following force. F1 is a force that biases the lock member by the spring, which is the biasing member, in the second direction when the plunger is in the first position. F2 is a force that biases the lock member by the spring, which is the biasing member, in the second direction when the plunger is in the second position. M1 is the force in the first direction received from the magnet when the plunger is in the first position. M2 is the force in the first direction received from the magnet when the plunger is in the second position. E is a force generated in the coil to move the plunger in the second direction. R is a force generated in the coil to move the plunger in the first direction.

(How to receive the force of the lock lever claw and cartridge door latch)
FIG. 9 shows the state of the lock lever that is the lock member and the cartridge door that is the opening and closing member under Condition 4. When the latch portion 205a of the cartridge door is pulled in the P direction, the lock lever 302 generates a rotational force in the Q direction, and the lock lever claw portion bites in. Specifically, there is a contact point C (a contact point between the latch portion 205a and the lock lever claw portion surface 302a) on an extension line in the P direction (opening direction of the cartridge door) from the rotation center 302b of the lock lever 302. The surface 302a of the lock lever claw is provided with an inclination of α degrees with respect to the surface of the cartridge door when the openable / closable cartridge door is closed. When viewed from a different viewpoint, the surface 302a of the lock lever claw portion is provided with an inclination of α degrees with respect to a straight line connecting the rotation center of the lock lever and the contact point.

  With this configuration, even if the user attempts to open the cartridge door, the force U input from the contact point C to the lock lever 302 is applied in a direction inclined by an angle α with respect to the P direction. The lock lever can maintain a locked state.

(Manual unlocking)
Manual unlocking means will be described with reference to FIG. If the holding solenoid or electrical parts break down and the lock unit does not operate, the cartridge door will not open. As a countermeasure for such a case, the lock can be manually released. Specifically, a small hole 320 a is opened in the left cover 320. When manually releasing the lock, the tip of the rod-shaped tool 321 is inserted into the hole 320a. Since the lock lever 302 is on the extended line of the hole 320a, when the tool is further pushed in, the lock lever rotates in the direction of the arrow in FIG. 10 and is unlocked. Since the hole 320a of the left cover is covered when the cartridge door is closed, it is difficult to see in appearance. That is, it is necessary to raise the cartridge door a little so that the rod-shaped tool 321 can be inserted into the hole 320a.

  The configuration described here is an example, and the manual unlocking method is not limited to this. For example, when there is a cover that can be opened and closed independently with respect to the cartridge door, the cover may be opened and the lock lever may be operated from the inside of the apparatus main body to release the lock.

(Shielding the magnetic field from the holding solenoid)
The holding solenoid constantly generates a magnetic field from the permanent magnet 301c. Further, when the coil is energized, a magnetic field is also generated by the electromagnet. For this reason, when a holding solenoid is installed in the vicinity of the cover of the apparatus main body as in this embodiment, it may be necessary to shield the magnetic field.

  As shown in FIG. 3, although the holding solenoid 301 is covered with the iron lock holder 305, the magnetic field leaks from the gap between the lock lever 302 and the lock holder 305. Since the lock lever moves between the lock position and the unlock position, the gap cannot be covered with the lock holder.

  Therefore, in this embodiment, the magnetic field is shielded by providing a shield plate on the cartridge door.

  FIG. 17 shows a detailed view of a part of the inside of the cartridge door.

  The cartridge door 205 is configured such that a shield plate 208 is sandwiched between the door outer cover 206 and the door inner cover 207 and fixed with a plurality of screws 209 (only one is shown).

  FIG. 18 shows the cartridge door with the door inner cover removed. The shield plate 208 is positioned by two positioning bosses 206b of the door outer cover 206. Further, a misassembly prevention rib 206c is provided to prevent misassembly.

  For reference, FIG. 19 shows the relationship between the cartridge door 205 including the shield plate 208 and the lock unit 300.

  In this embodiment, the shield plate 208 is made of iron, has a thickness of 0.4 mm, and has a size of 40 mm × 30 mm. As long as the thickness, size, material, and position of the shield plate are sufficient to absorb the magnetic flux, a configuration different from that of the present embodiment may be used. For example, by using a shield plate as a name plate or nameplate and sticking to a recess provided on the exterior surface of the door outer cover 206, the magnetic flux is shielded, or the door outer cover 206 itself is made of iron sheet metal. It is also possible to shield the magnetic flux while giving a high-quality appearance.

  In this embodiment, as shown in FIG. 2, when the cartridge door is opened, the cartridge door is obstructed so that the user cannot approach the lock unit. With this configuration, it is possible to prevent the magnetic field from the holding solenoid from being affected even when the opening / closing member is opened.

(Other)
In this embodiment, in order to attach and detach the cartridge, the cartridge door provided in the apparatus main body of the image forming apparatus so as to be openable and closable and movable between the first open position and the second closed position is locked. Although described, other objects may be locked. For example, the object may be a moving member such as a cartridge tray that holds cartridges, in addition to an opening and closing member such as a cartridge door. A lock mechanism that locks the sliding movement of a moving member such as a cartridge tray may be used.

  In the present embodiment, an image forming apparatus that employs a shield plate having a configuration different from that of the first embodiment will be described with respect to shielding of the magnetic field from the holding solenoid described in the first embodiment. In addition, what was comprised similarly to Example 1 attaches | subjects the same member name even if the same code | symbol or a code | symbol differs, and abbreviate | omits description.

  FIG. 20 is a perspective view of the lock unit installed in the apparatus main body. A lock unit is installed in the apparatus main body frame 401 as in the first embodiment. In the present embodiment, a lock unit cover 403 that covers the lock unit omitted in the first embodiment is also illustrated. A part of the lock lever 302 can be seen from the hole of the lock unit cover. (For the sake of explanation, FIG. 20 shows the lock lever in the locked position. However, when the cartridge door is opened, the lock lever is normally positioned in the unlocked position.)

  FIG. 21 is a perspective view in which the lock unit cover 403 is omitted. The lock unit of this embodiment is provided with an iron rocking shield plate 309 that is rockably supported by the lock lever 302 in order to shield the magnetic field radiated from the holding solenoid. In addition, the lock lever 302 is made of an iron-based sintered metal that is a ferromagnetic material (in Example 1, the lock lever does not need to be a ferromagnetic material and can be made of resin). . If the magnetic field radiated from the solenoid is sufficient, the surface of the lock lever may be coated with nickel, which is a ferromagnetic material. It doesn't matter. Further, the lock lever 302 may be made of resin as long as the lock holder 305 and the swing shield plate 309 can shield the magnetic field to the outside of the apparatus.

  Next, the configuration of the lock lever 302 and the swing shield plate 309 will be described with reference to FIG. (A), (b) has shown the figure from which a perspective direction differs, respectively. The swing shield plate 309 is supported so as to be swingable about the cylindrical boss 302c of the lock lever 302 and the rotation shaft 310 as a central axis. The lock lever 302 and the swing shield plate 309 are assembled by first inserting the cylindrical boss 302c into the hole of the swing shield plate 309, and then inserting the rotary shaft 310 from the inside of the lock lever into the other hole of the swing shield. The E-ring 308 is fixed to prevent the rotation shaft 310 from coming off.

  Next, the movement of the swing shield plate 309 will be described with reference to FIGS.

  FIG. 23 shows a state where the lock lever is located at the lock position. FIG. 24 shows a state where the lock lever is located at the unlock position. In the swing shield plate 309, the lock lever 302 moves between the locked position and the unlocked position. During this movement, the lock holder 305 and the lock unit cover 403 can be moved while swinging around the cylindrical boss 302c of the lock lever 302. 24 slides with the lock holder 305, and the sliding rib 403a of the lock unit cover 403 slides with the swing shield plate 309.

  With the configuration described above, the magnetic field from the holding solenoid can be shielded by the lock holder, the lock lever, and the swing shield plate. In Example 1, since a shield plate was provided on the cartridge door, which is an open / close member, the magnetic field could not be shielded when the open / close member was open. By configuring the shield plate as in the present embodiment, it is possible to shield the magnetic field even when the opening / closing member is open, and it is possible to increase the degree of freedom in designing the opening / closing method of the opening / closing member.

  An image forming apparatus including a lock mechanism according to the third embodiment will be described. In addition, what was comprised similarly to Example 1 and 2 attaches | subjects the same member name even if the same code | symbol or a code | symbol differs, and abbreviate | omits description.

(Lock mechanism)
In the first and second embodiments, the configuration in which the lock unit, which is a lock mechanism, is arranged on the front side of the frame of the main body of the image forming apparatus has been described. In this embodiment, a description will be given of a lock unit that is disposed on the back side of the frame.

  As shown in FIG. 11, the lock unit that is a lock mechanism includes a holding solenoid 301, a lock lever 501 that is a lock member, a lock lever shaft 502, and a pin that connects (engages) the lock lever 501 and the holding solenoid 301. Have Further, the lock unit includes a lock holder 503, a screw for fixing the holding solenoid 301 to the lock holder 503, and a spring 504 that is an urging member. The spring 504, which is an urging member, has a fixed end 504a hung on the hook 503a of the lock holder, and a free end 504b hung on the lock lever. One end of the lock lever shaft 502 is fixed by a lock holder 503 and the other end is fixed by a frame of the apparatus main body. The lock lever 501 is rotatable with respect to the lock lever shaft 502 while being biased by the spring 504.

  FIG. 12 shows a state where a lock unit, which is a lock mechanism, is attached to the main body of the image forming apparatus. The lock unit 500 is fixed to the apparatus main body frame 510 of the image forming apparatus by the screw 511 with the end portion 503b of the lock holder abutting against the side surface of the apparatus main body frame 510. If the lock lever 501 is locked and the cartridge door 205 is to be opened in the P direction, a force is received by the apparatus main body frame 510 via the lock unit 500, so that a large force can be withstood.

  In this embodiment, since the lock unit is installed in the space inside the apparatus main body frame 510, the distance from the outside of the main body is increased, and the main body frame shields the magnetic field from the holding solenoid. The shield plate required in 1 and 2 is not necessary.

(How to receive the force of the lock lever claw and cartridge door latch)
In this embodiment, as shown in FIG. 13, the surface 501a of the lock lever claw is formed so as to be concentric with the rotation center 501b. In such a configuration, even when the user tries to open the cartridge door, the force W input from the latch portion 205a to the lock lever 501 acts substantially in parallel with the P direction for opening the door. For this reason, it is not converted into the force in the rotation direction of the lock lever, and the locked state can be maintained.

  An image forming apparatus including a lock mechanism according to Embodiment 4 will be described. In addition, what was comprised similarly to Example 1, 2, and 3 attaches | subjects the same member name even if the same code | symbol or a code | symbol differs, and abbreviate | omits description.

  The locking mechanism of this embodiment is shown in FIGS. 14 shows a locked state in which the opening / closing member is locked, and FIG. 15 shows a unlocked state in which the locking of the opening / closing member is released. The lock mechanism of the present embodiment mainly includes a holding solenoid 301, a lock lever 602 that is a lock member, and a spring 603 that is an urging member. A lock lever 602 as a lock member is connected (engaged) with a plunger 601 of a holding solenoid via a pin 304. A lock lever 602 that is a lock member is held to be slidable in the X direction with respect to the apparatus main body of the image forming apparatus, and slides in the same direction in conjunction with the sliding operation of the plunger 601. The lock lever 602 has a lock claw 602a.

  In FIG. 14, the plunger is in the second position, and the lock member locks the opening / closing member (lock position). Similarly, in FIG. 15, the plunger is in the first position, and is in an unlocked state (unlocked position) in which the lock of the opening / closing member is released. That is, the lock position is the second position, the lock release position is the first position, and is in a reverse relationship to the position of the first embodiment.

  In the state shown in FIG. 14, the lock lever, which is a lock member, is engaged with the latch portion 205a of the cartridge door. Therefore, even if the cartridge door 205 is opened in the P direction, it is not opened. After energizing the holding solenoid and moving the plunger to the first position (that is, after transitioning to the state of FIG. 15), the lock pawl 602a is in the unlocked state retracted from the latch 205a, so the cartridge door 205 is Can open in the P direction.

  Next, the relationship between forces will be described. At the right end of the lock lever 602 shown in FIG. 14, the permanent magnet attractive force M2 by the holding solenoid acts in the right direction, which is the second direction, and at the left end, the urging force F2 by the spring 603 as the urging member is first. It works in the left direction, which is one direction. The permanent magnet attractive force M2 is a strong force with the plunger tip 601a abutting against the bottom 301a of the holding solenoid. By setting the biasing force F2 in the first direction to a force smaller than the permanent magnet attractive force M2 in the second direction, the lock lever 602 that is the lock member is held in a state of being pulled in the right direction that is the second direction. Is done. On the other hand, in the state of FIG. 15, the plunger tip 601a is separated from the solenoid bottom 301a, and the permanent magnet attractive force M1 is lower than the permanent magnet attractive force M2. By setting the biasing force F1 in the first direction to a force larger than the permanent magnet attractive force M1, the lock lever 602 is held in a state of being pulled rightward.

  In the first, second, and third embodiments, the state in which the plunger is pulled into the holding solenoid is in the unlocked state, whereas in this embodiment, the state in which the plunger is pulled into the holding solenoid is in the locked state. It has become. The relationship between the plunger position of the holding solenoid (retracted state / push-out state) and the lock position (locked state / unlocked state) is not limited to one, and can be freely selected depending on the configuration It is.

  In the present embodiment, the case where the lock lever claw and the cartridge door claw are each formed by one holding solenoid has been described. However, the present invention is not limited to this. The lock lever, which is a lock member, and the cartridge door, which is an opening / closing member, have a plurality of engaging portions that engage with each other, and a single holding solenoid engages latches at a plurality of locations on the cartridge door. Good.

205 Opening / closing member 208 Shield plate 300 Lock mechanism 301 Solenoid 302 Lock member 307 Energizing member 401 Device main body frame 500 Lock mechanism 501 Lock member 504 Energizing member 510 Device main body frame 602 Lock member 603 Energizing member

Claims (14)

An opening and closing member that can be opened and closed with respect to the apparatus main body of the image forming apparatus;
A locking member for locking the opening and closing member;
A biasing member that biases the lock member;
The plunger is moved to a first direction and a second direction opposite to the first direction, and is engaged with the lock member and energizes the plunger that biases the lock member, thereby causing the plunger to move to the first position and the first position. A solenoid having a coil that moves between the second position moved in the second direction from the second position, and a magnet having a magnet that applies a magnetic force to the plunger in a non-excited state,
An image forming apparatus satisfying the following expression in the non-excited state:
F2 <M2
F1> M1
F1 is a force in the first direction that biases the lock member by the biasing member when the plunger is in the first position,
A force in the first direction for biasing the lock member by the biasing member when the plunger is in the second position is F2,
The force in the second direction acting on the plunger from the magnet when the plunger is in the first position is M1,
M2 is a force in the second direction that acts on the plunger from the magnet when the plunger is in the second position. The image forming apparatus according to claim 1, wherein the following expression is satisfied in an excited state.
F1 <M1 + E
F2 + R> M2
E, the force generated from the coil to move the plunger in the first direction,
R is the force generated from the coil to move the plunger in the second direction. An opening and closing member that can be opened and closed with respect to the apparatus main body of the image forming apparatus;
A locking member for locking the opening and closing member;
A biasing member that biases the lock member;
The plunger is moved to a first direction and a second direction opposite to the first direction, and is engaged with the lock member and energizes the plunger that biases the lock member, thereby causing the plunger to move to the first position and the first position. A solenoid having a coil that moves between the second position moved in the second direction from the second position, and a magnet having a magnet that applies a magnetic force to the plunger in a non-excited state,
An image forming apparatus satisfying the following expression in the non-excited state:
F1 <M1
F2> M2
F1 is a force in the second direction that biases the lock member by the biasing member when the plunger is in the first position,
A force in the second direction for urging the lock member by the urging member when the plunger is in the second position is F2,
The force in the first direction acting on the plunger from the magnet when the plunger is in the first position is M1,
A force in the first direction acting on the plunger from the magnet when the plunger is in the second position is M2. The image forming apparatus according to claim 3, wherein the following expression is satisfied in an excited state.
F2 <M2 + R
F1 + E> M1
E, the force generated from the coil to move the plunger in the second direction,
R is the force generated from the coil to move the plunger in the first direction. A cartridge that can be attached to and detached from the main body of the image forming apparatus;
5. The image according to claim 1, wherein the opening / closing member is movable between a first open position that exposes the cartridge and a second closed position that covers the cartridge. 6. Forming equipment. The lock member has a surface in contact with the opening and closing member,
The image forming apparatus according to claim 1, wherein the surface is inclined with respect to the surface of the opening / closing member in a state where the opening / closing member is closed. The lock member is movable between a lock position for locking the opening / closing member and a release position where the lock of the opening / closing member is released,
The image forming apparatus according to claim 1, wherein the urging member urges the lock member in a direction in which the lock member moves to a lock position. The lock member is movable between a lock position for locking the opening / closing member and a release position where the lock of the opening / closing member is released,
The image forming apparatus according to claim 3, wherein the urging member urges the lock member in a direction in which the lock member moves to a release position.   9. The ferromagnetic material according to claim 1, wherein a ferromagnetic material is installed at a position that is at least a part of the opening / closing member and shields a magnetic field radiated from the solenoid to the outside of the image forming apparatus. The image forming apparatus according to claim 1.   9. The image forming apparatus according to claim 1, wherein a ferromagnetic material for shielding a magnetic field radiated from the solenoid is installed on at least a part of the lock member. 10. .   The image forming apparatus according to claim 1, wherein the solenoid is installed in an apparatus main body made of a ferromagnetic material. A locking member for locking the object;
A biasing member that biases the lock member;
The plunger is moved from the first position and the first position by exciting with a plunger that is movable in a first direction and a second direction opposite to the first direction, engages with the lock member and biases the lock member. A solenoid having a coil that moves between the second position moved in the second direction and a magnet that causes a magnetic force to act on the plunger in a non-excited state,
The plunger can be held in the first position by the biasing force of the biasing member being greater than the magnetic force of the magnet in a non-excited state,
A locking mechanism characterized in that, in a non-excited state, the plunger can be held at the second position because the biasing force of the biasing member is smaller than the magnetic force of the magnet. A locking member for locking the object;
A biasing member that biases the lock member;
The plunger is moved from the first position and the first position by exciting with a plunger that is movable in a first direction and a second direction opposite to the first direction, engages with the lock member and biases the lock member. A solenoid having a coil that moves between the second position moved in the second direction and a magnet that causes a magnetic force to act on the plunger in a non-excited state,
The plunger can be held in the second position by the biasing force of the biasing member being greater than the magnetic force of the magnet in a non-excited state,
A locking mechanism characterized in that the plunger can be held at the first position because the biasing force of the biasing member is smaller than the magnetic force of the magnet in a non-excited state. 14. The image forming apparatus according to claim 12, wherein a ferromagnetic material for shielding a magnetic field radiated from the solenoid is installed on at least a part of the lock member.

Images