JPH06236104A - Image recorder - Google Patents

Abstract

(57) [Summary] [Structure] The clam shell 800 is provided with the rollers 26 that come into contact with the developing unit 2. Further, a set leaf spring 83 having a high spring constant that generates a high pressing force before reaching the predetermined position but a low pressing force at the predetermined position and a pressing leaf spring 84 that generates a weak pressing force with a low spring constant are provided. [Effect] By the action of the rollers, the frictional force between the clam shell and the developing unit becomes small, and the pressing force can be easily controlled. Furthermore, the set leaf spring secures the settability of the developing unit, and the pressing leaf spring substantially presses the developing unit with a weak force, thereby limiting the inflow of torque from the developing roller to the photosensitive member and reducing the amount of jitter. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image recording apparatus.

[0002]

2. Description of the Related Art Conventionally, various developing methods, for example,
The electrophotographic image recording apparatus, such as whether the developing roller is brought into contact with the photoconductor or not, and whether the toner is magnetic, nonmagnetic, or a magnetic developer, that is, whether or not a carrier is used, is used. Proposed. Among them, the non-magnetic one-component contact type developing device that uses the non-magnetic toner that does not have magnetic properties to bring the developing roller into contact with the photoconductor and that does not use the magnetic developer can be easily configured. Many inventions have been made. For example, JP-A-1-252979, in which the peripheral speed of the developing roller is made faster than the peripheral speed of the photosensitive member in order to improve the developing performance, JP-A-2-208671 in which an elastic roller having a rubber surface is used as the developing roller. Publications and the like are disclosed.

[0003]

The non-magnetic one-component contact type developing device has the advantage of simple structure.
In this method, the developing roller using an elastic body such as rubber having a high friction coefficient on the surface is pressed against the photoconductor, and the peripheral speed of the developing roller is set higher than that of the photoconductor in order to improve the developing performance. Therefore, a large rotational torque acts on the photoconductor due to the frictional force with the developing roller. As described above, the peripheral speed of the developing roller is faster than the peripheral speed of the photoconductor,
The photosensitive member receives a rotational force that tends to rotate faster than a predetermined rotational speed due to the rotational torque flowing from the developing roller. The gear train connected to the photoconductor tries to rotate the photoconductor accurately, but the rotational torque generated by the frictional force with the developing roller impedes the accurate rotation of the photoconductor. For this reason, there is a problem that the rotation of the photoconductor becomes irregular, and the image is easily deteriorated such as the occurrence of jitter in the recorded image. In particular, if the pressing force that presses the developing roller against the photoconductor becomes excessively large, this tendency becomes remarkable. Therefore, it is absolutely necessary to avoid applying an excessive pressing force.

Further, in the non-magnetic one-component contact type developing device, the developing roller is strongly pressed by the doctor blade to frictionally charge the toner, so that the load torque of the developing unit is large. Therefore, to drive this large load,
A large force acts on the developing unit from the drive system. As described above, the smaller the pressing force between the developing roller and the photoconductor is, the better, and it is desirable that the force acting from the drive system on the developing unit having the developing roller is not directed toward the photoconductor. For this purpose, the direction of the force acting on the developing unit may be directed perpendicular to the direction of the photoconductor. However, since the force acting on the developing unit is large as described above, the frictional force due to this force is large,
The force that presses the developing unit having the developing roller against the photoconductor is blocked by this large frictional force, and there is a problem that control becomes difficult.

On the other hand, since the developing unit is constructed so as to be pressed in the direction of the photoconductor, it has the freedom of movement in the direction of the photoconductor. When the developing unit is configured to be attached and detached for the purpose of replenishing toner and the like, a configuration capable of reliably setting the developing unit at a predetermined position against the degree of freedom is required. The spring that presses the developing unit toward the photoconductor is composed of a leaf spring, and it is possible to secure the settability by guiding with this leaf spring, but it is possible to secure a developing unit that weighs nearly 1 kg when toner is filled. A large spring force is required to set it in place. However, as described above, when the force for pressing the developing unit toward the photoconductor is increased, there is a problem in that a recorded image has jitter and the image is disturbed.

An object of the present invention is to make it easy to control the pressing force of the developing unit toward the photosensitive member and to press the developing unit with a low pressing force while ensuring the setting property of the developing unit. An object of the present invention is to provide an image recording apparatus capable of obtaining a recorded image with high print quality.

[0007]

The above-described object is to provide a scanning optical system, a photoconductor on which an electrostatic latent image corresponding to an image signal is formed by laser light emitted from the scanning optical system, and the photoconductor. In an image recording apparatus having a developing unit for developing toner, the developing unit having a developing roller in contact with the photoconductor, a supporting member for holding the developing unit, and a sheet conveying unit for conveying a sheet, This is achieved by providing rollers that abut the developing unit.

In addition to this structure, as means for pressing the developing unit toward the photosensitive member, a pressing force for pressing the photosensitive member by the developing roller is applied to a predetermined position where the developing roller in the developing unit contacts the photosensitive member. A pressure spring that is generated,
Even if two types of pressure springs are used, a low pressure force is generated for the pressure spring at the predetermined position, but a high pressure force is generated for the pressure spring at a position that does not reach the predetermined position. Good.

[0009]

With the above structure, the pressing force of the developing unit against the photosensitive member can be reduced.

That is, since the frictional force between the developing unit and the supporting member becomes small due to the action of the rollers and the pressing force can be easily controlled, a low pressing force can be set.
In addition, a spring that generates a high pressing force at a position where the developing unit does not reach the predetermined position and a low pressing force at the predetermined position ensures the settability, and when the developing unit reaches the predetermined position, the setting force is substantially reduced. By weakly pressing the developing unit toward the photosensitive member by the spring that generates a low pressing force, weak pressing between the developing unit and the photosensitive member can be realized. As a result, the torque flowing from the developing roller to the photosensitive member does not become excessive, and the amount of jitter generated in the image can be suppressed to a small value.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an image recording apparatus of the present invention.

First, the overall structure will be described with reference to FIG.
A paper cassette 351 that constitutes a paper storage unit is housed in the image recording apparatus body 900. The paper 311 is stored in the paper cassette 351 that constitutes the paper storage unit. Further, the paper feed roller 321 is arranged at the leading end side of the paper in the paper cassette 351 in the conveyance direction, and the registration rollers 371 and 372 constituting the paper skew correction member are arranged in front of the photoconductor 1. The registration rollers 371 and 372 correct the skew of the sheet and perform the sheet feeding operation. The recorded sheets are accumulated on the sheet tray 388.

The scanning optical system 381 is a laser diode,
It is composed of a polygon mirror and an F-θ lens and is fixed to the clamshell 800. The laser light emitted from the scanning optical system 381 forms an electrostatic latent image according to an image signal on the surface of the photoconductor 1 that constitutes the photoconductor unit 10. As shown in FIG. 2, the developing unit 2 has a hopper 201 for accommodating the toner 21 therein, a developing roller 23, and the like, and the toner is developed on the photoconductor 1. The transfer corotron 383 uses a high voltage circuit (not shown) to add a few k
A high voltage of V is applied, and the toner on the photoconductor 1 is transferred onto the paper by the action of electrostatic force. Thermal fuser 387
Heats and fixes the paper having the toner image on its surface to form a permanent image.

The recording operation of the image recording apparatus of the present invention will be described below. First, with a controller (not shown)
The warm-up of the fixing device 387 is started and the polygon mirror of the scanning optical system 381 is rotated. Fixer 3
When the 87 and the scanning optical system 381 become operable,
The paper feeding operation is started.

When a paper feed command is issued from the controller, a motor (not shown) rotates. This rotational driving force is transmitted to the sheet feeding roller 321 via the gear, and the sheet feeding roller 321 separates and conveys the sheet 311. The sheet 311 separated from the sheet cassette 351 is conveyed in a conveying path formed by the sheet guides 362 and 363 and the lower surface of the developing unit 2 by the rotation of the sheet feeding roller 321, and a registration roller 371 that is a sheet skew correction member. , 372. At this time, the sheet is stopped by the registration rollers 371 and 37.
Even after hitting the contact portion of No. 2, the sheet is further conveyed and skew is corrected. After that, the registration roller starts rotating,
The sheet is conveyed along the sheet guide 364.

On the other hand, a high voltage of several kV is applied to the charger 14 provided in the photoconductor unit 10, and the surface of the photoconductor 1 is uniformly charged by the ions generated by the charger 14. The scanning optical system 381 that has received the image signal writes a pattern by the laser light on the photoconductor 1 that rotates according to the image signal. The toner on the photoconductor 1 is developed by the developing unit 2 to form a visible image with the toner, which is transferred onto the conveyed sheet at a predetermined timing. The sheet on the surface of which the toner image has been transferred is guided to the sheet guide 365 and conveyed to the fixing device 387. The sheet 311 is a fixing device 387.
After being fixed by the heat of the sheet, the sheet is discharged to the sheet tray 388, and the recording operation is completed.

An embodiment of the developing unit will be described below with reference to the drawings. First, description will be made with reference to FIGS. 2 to 3. Figure 2
3 is a partial cross-sectional side view of the developing unit, and FIG. 3 is a top view of the developing unit.

The clam shell 800 constituting the developing unit supporting member is made of a zinc-plated steel plate having a thickness of 1.6 mm and is formed into a large L-shape. At its lower end, a clamshell fulcrum 802 for opening and closing the clamshell 800, a clamshell opening 803 provided at the upper center for irradiating laser light from an exposing means (not shown), and the developing unit 2 are provided. It has a clamshell rail 801 for supporting the. The developing unit 2 is supported by the clamshell 800. Further, a guide member 82 for guiding the developing unit 2 and the photoconductor unit 10 are fixed to the clamshell 800. Further, a roller 26 that is in contact with the developing unit is fixed to the clamshell 800. The roller 26 is perpendicular to the direction of the photosensitive member as seen from the developing unit indicated by arrow e in FIG. 2 and the direction of the photosensitive member as seen from the developing unit indicated by arrow E in FIG. Two
It is configured to be rotatable in two directions, that is, two positions on the upper part of the developing roller 23 and the upper part of the hopper 201 that stores the toner 21, and two positions at target positions with respect to two positions in the depth direction of the paper in FIG. There are 4 locations in total. Furthermore,
Two types of leaf springs, a pair of set leaf springs 83 for setting the developing unit and a pair of pressing leaf springs 84 for pushing the developing unit, are arranged in the clamshell 800. The set leaf spring 83 generates a pressing force of about 2 kgf at maximum with the total load of the two leaf springs, but since the spring constant is high, the developing unit is pushed by the set leaf spring and moves toward the photoconductor, and the developing roller 23 The pressing force is set to be substantially small when a predetermined position, which is a position where the photosensitive member 1 contacts the photoconductor 1, is reached. The pressing force of the pressing leaf spring 84 is set to a low value of about 500 gf as the total load of the two leaf springs. Further, since the spring constant of the pressing leaf spring 84 is set low, the set pressing force is kept substantially constant regardless of the machine difference. There are two types of means for pressing the developing unit in the direction of the photoconductor, namely, a pressing spring that has a low spring constant and generates a weak pressing force, and a pressing spring that has a high spring constant and generates a high pressing force with respect to the pressing spring. By using the pressing spring of No. 2, it is possible to set the pressing force between the developing roller and the photosensitive member to be low while ensuring the setting property of the developing unit, so that a good image without jitter can be obtained.

The photosensitive body 1 having a cylindrical shape has a base body coated with a photosensitive material on a conductive material, for example, an aluminum alloy, and the conductive base body is electrically set to a potential of 0V. Is held. The photoconductor 1 is rotated at a constant speed in the direction of arrow A by a drive source (not shown). Since the direction of arrow A shown in FIG. 2 is the direction in which an image is formed on the photoconductor 1, this will be hereinafter referred to as the recording direction of the photoconductor 1.

A recording process member that rotates or moves while being in contact with the photoconductor and has the same velocity vector as that of the photoconductor 1 at the contact point with the photoconductor will be considered as the same as the recording direction of the photoconductor 1. In this embodiment, the rotational speed of the photoconductor is 35 mm / s and the diameter of the photoconductor is 30 mm.

The photoconductor unit 10 is fixed to the clamshell 800 of the image recording device by screws. The thickness 2 fixed to the plate member 12 is provided inside the photoconductor unit 10.
Cleaning blade 11 made of mm urethane rubber,
The screw 13 for carrying the toner cleaned by the cleaning blade 11, the seal plate 15 made of urethane rubber having a thickness of 0.2 mm for preventing the toner carried by the screw 13 from dropping, and the surface potential of the photoconductor 1 from -300 to -9.
A charger 14 for maintaining a constant voltage of about 00V is provided.

The developing unit 2 includes a rail 801 and a clamshell 800 of a clamshell 800 of the image recording apparatus.
It is supported by a guide member 82 that is fixedly attached thereto in the direction of arrow E so that it can be inserted and removed. The developing unit 2 has a degree of freedom in which it can be moved in the direction of the photoconductor and in the direction opposite to the photoconductor indicated by the arrow e by the clamshell rail 801 and the guide member 82. In the developing unit 2, a pressed member 283 having a central recess at positions facing the two set leaf springs fixed on the clamshell 800.
Is equipped with. The setting leaf spring 83 has a function of exerting a click feeling when the developing unit 2 is replaced by pressing the depression in the center of the pressed member 283, and confirms that the developing unit is surely set to the predetermined position. be able to.

Bearings 260 made of polyacetal resin are fixed to the developing unit 2 on both side plates of the developing unit 2 on the side of the photosensitive member, and the developing roller 23 and the conveying roller 24 are provided.
Is rotatably supported. The stirring blade 25 is also rotatably supported by the developing unit, and the developing roller 23, the transport roller 24 and the stirring blade 25 are driven by gears in the directions of arrows B, C and D respectively. The developing roller 23 has a diameter of 16 mm and a diameter of 10 mm.
The core metal is coated with conductive urethane rubber having a rubber hardness of Hs35 ± 5 °, and rotates while contacting the photoconductor 1 by the pressing force of the pressing leaf spring, and the rotation direction is
The same recording direction is set. The rotation speed of the developing roller 23 needs to be higher than the rotation speed of the photoconductor in order to increase the toner supply amount and improve the developing performance.
In this embodiment, the peripheral speed is set to 63 mm / s, which is about 1.8 times the rotational speed of the photoconductor. The developing roller 23 is
A voltage of about −150 to −200 V is applied to the core metal from the main body of the image recording apparatus via a contact (not shown). The transport roller 24 is a roller having a sponge-like surface. A developing blade 27 made of a metal such as aluminum alloy or brass is slidably supported by the developing unit 2, and a linear pressure of 86 g /
cm (84.2 N / m) and the total pressure when the recording width is 256 mm is 2.2 kg (21.6 N) under the condition of the developing roller 23.
Has been pressed. Hopper 2 in developing unit 2
Reference numeral 01 contains a non-magnetic toner 21, and the toner 2 is rotated by the rotation of a stirring blade 25 composed of an elastic blade.
1 is sent to the transport roller 24. The carrying roller 24 carries the toner 21 to the developing roller 23, and the toner 21 on the developing roller 23 is rubbed by the developing blade 27 to be triboelectrically charged to a desired polarity, in this embodiment, a negative polarity. In the developing unit, when the developer in the hopper 201 is exhausted, the user opens the clamshell 800 and sets the developing unit 2 to the rail 801 of the clamshell 800 of the image recording apparatus.
The guide member 82 can be taken out by sliding it, and can be easily replaced with a new one. The roller 26 is configured to be rotatable with respect to two moving directions, that is, the direction of the photoconductor viewed from the developing unit and the direction orthogonal to the direction of the photoconductor.

An exposure unit (not shown) is fixed to the upper portion of the clamshell 800 and passes through the gap between the photoconductor unit 10 and the developing unit 2 from the clamshell opening 803 in accordance with an image signal and the laser light 66 is emitted. To form an electrostatic latent image on the photoconductor 1.

The operation of the above configuration will be briefly described. The photosensitive member 1 rotating in the A direction is irradiated with the laser beam 66 by the exposing means to form an electrostatic latent image on the surface of the photosensitive member 1. Since the potential of the electrostatic latent image is about 0 to −150 V, the negatively charged developer on the developing roller 23 to which the voltage of −150 to −200 V is applied adheres to the electrostatic latent image. As a result, a developed image is formed on the photoconductor 1. In this developed image, most of the toner is transferred onto the recording sheet by a transfer unit (not shown) and is fixed by a thermal fixing device (not shown). A small amount of toner that has not been transferred is scraped off by the cleaning blade 11, conveyed by the screw 13, and stored in a waste toner container (not shown). Further, when the photoconductor 1 rotates in the A direction, the photoconductor 1 is charged again by the charger 14.

Next, the specific structure of the power transmission of the embodiment shown in FIGS. 2 and 3 will be described with reference to FIGS. 4, 5 and 6. 4 is a side view showing the entire structure of power transmission by gears, FIG. 5 is an enlarged perspective view of a part of FIG. 4, and FIG. 6 is an explanatory view of a force relationship of a part of the gear train of FIG. . The circle indicated by the alternate long and short dash line in the figure indicates the pitch circle of the gear.

The drive motor 90 is the main body 9 of the image recording apparatus.
It is fixed at 00. The drive motor has a maximum torque of 1.
It is a 9kgcm stepping motor with a rotation angle of 1.8 degrees.
It is driven at a driving frequency of 1900 pulses / sec. The gear 101 fixed to the shaft of the drive motor 90 rotates counterclockwise. Gears 102, 103, 104, 107 and 1
08 is rotatably fixed to the main body 900 of the image recording apparatus. Gears 104 and 109 are 103 and 108, respectively.
Is supported by lever bodies 120 and 121 that maintain the pitch of the gears as the fulcrum of rotation, and gears 105 and 106 are provided in the photoconductor unit. Springs 122 and 123 are provided to bias the lever bodies 120 and 121 toward the gears 105 and 110, respectively. As shown in FIG. 5, the gear 109 and the gear 110 are provided with pressure contact rings 209 and 210, respectively, which freely rotate coaxially. This pressure welding ring 209 and 2
The diameter of 10 is set to be the same as the diameter of the pitch circles of 109 and 110, respectively, and serves to keep the distance between the gear 109 and the gear 110 accurate. The gears 104 and 105,
The same as the press contact ring provided on the gear 109 and the gear 110 is provided. Also, the gears 110, 111, 1
12, 113, and 114 are provided in the developing unit. Gear 101 fixed to the shaft of drive motor 90
Is a stepped gear 102, a stepped gear 103 and a gear 10.
4 are rotated in the directions indicated by the arrows, respectively, and the photoconductor 1
Then, the gear 105 fixed to is rotated to rotate the photoconductor 1. Further, the gear 105 fixed to the photoconductor 1 rotates the gear 106 fixed to the screw 13.

Further, the gear 101 fixed to the shaft of the drive motor 90 causes the gears 102, 107, 108 and 109 to rotate in the directions indicated by the arrows, and the gear 110 fixed to the conveying roller 24 to rotate. Then, power is transmitted to the developing unit 2. In the developing unit 2, the gear 11
From 0, the gear 111 is rotated in the direction indicated by the arrow to rotate the gear 112 fixed to the developing roller 23,
The gear 114 to which the stirring blade 25 is fixed is rotated via the gears 111 and 113.

Since the developing unit 2 has a degree of freedom of movement in the direction of the photosensitive member, the lever body 121 causes the position of the gear 109 to follow the position of the developing unit.

As described above, the developing roller 23 is strongly pressed by the developing blade 27 and has a high rotational speed. Therefore, a large torque is required to rotate the developing roller 23. Therefore, due to the rotating action of the gear 109, a large force acts on the developing unit 2 via the gear 110.

The relationship between these forces will be described with reference to FIG. Figure 6
Is a consideration of the forces acting on the gears 108, 109, 110. In this embodiment, the angle formed between the gear 109 attached to the tip of the lever body 121 and the first stage gear 110 of the developing unit with respect to the horizontal line is α, and the gear 108.
If the angle formed by and is β, α and β have the same angle. The drive motor 90 rotates and the gears 108, 109 and 110 of FIG. 6 rotate. At this time, the gear 110 receives from the gear 109 a tangential force H proportional to the load torque of the developing unit indicated by the arrow H. This tangential force H is upward and is in the direction opposite to the photoconductor. This tangential force H is
As is well known, the gears are inclined by the pressure angle θ with respect to the tangent to the pitch circle of the gears 109 and 110. In this embodiment, it is inclined by 20 degrees. At the same time, the gear 109 receives a tangential force h from the gear 110 as a reaction of the tangential force H. The gear 109 receives from the gear 108 a tangential force H or a tangential force j whose absolute value is the same as the tangential force h and is proportional to the load torque of the developing unit. The tangential force j is also inclined by the gear pressure angle with respect to the tangent to the pitch circle of the gears 109 and 108. The tangential forces h and j acting on the gear 109 are translated to the center of the gear 109 to generate a force h ′,
The resultant force that is the vector sum of j'is the force k shown in the figure. The forces obtained by decomposing this resultant force k in the directions of the gears 108 and 110 are forces n and m shown in the figure. The force m acts as a force by which the gear 109 compresses the lever body 123 in the direction of the gear 108. The force n acts as a force for pressing the developing unit 2 in the upward direction and the photoconductor direction via the pressing ring 209 coaxial with the gear 109 via the pressing ring 210 coaxial with the gear 110. Therefore, the developing unit includes the gear 110 and the pressure contact ring 210.
A tangential force H and a force n are received via. When the vector sum of the tangential force H and the force n is calculated by the force n ′ obtained by translating the force n, the resultant force of the tangential force H and the force n is the force p shown in the figure. This force p
The direction of is only the upward component. Therefore, the force p acting on the developing unit from the drive system acts only in the direction perpendicular to the photoconductor, and does not increase the force pressing the developing unit toward the photoconductor.

However, the force p acting on the developing unit has a very large value. For example, when the load torque of the developing unit is 3 kgcm, the absolute value of the force p is 4 kgf. A
The coefficient of friction between the developing unit made of BS resin and the clamshell made of galvanized steel sheet is about 0.3, so if there is no roller in the clamshell, a normal force of 4 kg acts: The frictional force is a very large value of 1.2 kg, and it becomes very difficult to control the pressing force for pressing the developing unit toward the photoconductor.

However, when the roller of the present invention is used, the frictional force becomes a small value that can be ignored and the pressing force is easily controlled, so that a low pressing force can be set and a good image without jitter can be obtained. Can be obtained.

In the present embodiment, as described above, the rollers are the target positions with respect to the upper part of the developing roller 23, the upper part of the hopper 201 that stores the toner 21, and the two positions in the depth direction of the paper in FIG. It is located at a total of four locations, two at each location. However, as described above, the force acting on the developing unit from the drive system is transmitted via the pressure contact ring 210 coaxial with the gear 110, so that the roller is installed only at one position near the lowest gear 110. good.

In this embodiment, the developing unit 2 is attached and detached in the direction of arrow E, which is a direction perpendicular to the photoconductor. However, the attaching and detaching direction of the developing unit is the direction of the photoconductor indicated by arrow e. Even if there is, the effect of the present invention is the same. Furthermore, even if the developing unit is not attached or detached,
The effects of the present invention are the same as long as the developing unit has a structure that allows the developing unit to move toward the photoreceptor.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a side view of a partial cross section showing the main part of the image recording apparatus according to the second embodiment of the present invention. FIG. 8 is a side view of a part of the developing unit and the clam shell shown in FIG. 7 as viewed from the side opposite to the photoconductor. In this embodiment, the roller 326 is a roller that can rotate only toward the photoconductor. The roller 326 is composed of a ball bearing and is inserted into the shaft 322 supported by the support block 321 by press fitting. Around 32
The top portion 327 of the upper outer wall of the developing unit 2 that comes into contact with the developing unit 6 is lower than the portion 328 that comes into contact with the rollers 326 when the developing unit is attached and detached. Also, 327
And the 328 part, the curved surface part 3 that changes smoothly
28 is provided. When the user inserts the developing unit into the clamshell, the developing unit is inserted in the direction indicated by arrow E. Since the roller 326 needs to contact the upper outer wall of the developing unit, the roller 326 projects from the lower surface of the sheet metal of the clamshell 800. However, as described above, since the leading portion 327 of the upper outer wall of the developing unit 2 when the developing unit is attached and detached is lower than the portion 328 that comes into contact with the rollers, the outer wall of the upper portion of the developing unit comes into contact with this portion. There is no such thing. Further, since the curved portion 329 that smoothly changes is provided at the boundary between the lower portion 327 of the outer wall of the developing unit upper portion and the portion 328 where the outer wall of the upper portion of the developing unit contacts.
By the action of the curved surface portion, the insertion of the developing unit can be completed smoothly. In this example, a smoothly changing curved surface portion 329 is provided at the boundary between the lower portion 327 of the developing unit upper outer wall and the portion 328 that is in contact with the developing unit upper outer wall. 329 may be a flat portion having a small gradient.

[0037]

According to the present invention, the pressing force of the developing unit toward the photosensitive member can be easily controlled, and the developing unit can be pressed with a low pressing force while ensuring the setting property of the developing unit. A recorded image with high print quality can be obtained with a simple configuration.

[Brief description of drawings]

FIG. 1 is a side view of the entire image recording apparatus of the present invention.

FIG. 2 is a side view of a partial cross section of a main part of an image recording apparatus showing an embodiment of the present invention.

FIG. 3 is a partial cross-sectional top view of the main part of the embodiment of the present invention shown in FIG.

FIG. 4 is a side view showing the entire power transmission of one embodiment of the present invention.

5 is a perspective view of a portion of FIG.

FIG. 6 is an explanatory diagram of a force relationship of a gear train.

FIG. 7 is a side view of a partial cross section of a main part of an image recording apparatus showing another embodiment of the present invention.

FIG. 8 is a side view of a partial cross section of the main part of the embodiment of the present invention shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photosensitive member, 2 ... Developing unit, 10 ... Photosensitive member unit, 23 ... Developing roller, 24 ... Conveying roller, 26 ... Roller, 27 ... Developing blade, 66 ... Laser beam, 83 ... Set leaf spring, 84 ... Press plate Springs, 101, 102, 10
3, 104, 105, 106, 107, 108, 10
9, 110, 111, 112, 113, 114 ... Gears,
121 ... Lever body, 123 ... Spring, 326 ... Roller.

Claims (1)

[Claims] 1. A scanning optical system, a photoconductor on which an electrostatic latent image corresponding to an image signal is formed by laser light emitted from the scanning optical system, and toner development on the photoconductor. In an image recording apparatus having a developing unit including a developing roller that comes into contact with the photoconductor, a supporting member that holds the developing unit, and a sheet conveying unit that conveys a sheet, a roller that comes into contact with the developing unit with the supporting member. An image recording apparatus comprising: