JPH04280258A - Image formation device - Google Patents

Abstract

PURPOSE:To provide an image formation device having the capability of increasing an amount of developer supplied at one time without expanding space for placing a developer container. CONSTITUTION:In an image formation device for generating an image by an electrophotographic method, a sheet delivery section 23 having a shorter overall length than a sheet breadth is provided along an axial center orthogonal with a sheet delivery direction. In addition, a developer container 22 is so provided as to have a developer storage section 77 extended from the vicinity of a photo- sensitive body 24 to the outside of the edge of the sheet delivery section 23 in an axial direction. The storage amount of developer is thereby increased, while a frequency for supplying the developer is reduced. Also, the dead space of the sheet delivery section 23 above the axial line thereof is employed to position the developer storage section 77, thereby ensuring the compact design of an image formation device.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus that forms images based on electrophotography.

0002

[Prior Art] Conventionally, a charged part, an exposed part,
There is an image forming apparatus in which process units such as a developing section and a transfer section are arranged, and a paper transport section and a fixing section are arranged along a paper transport path.

0003

Problems to be Solved by the Invention In order to reduce the frequency of replenishing the developer container with developer, a large developer container is required. In order to satisfy this requirement, a sufficient space must be ensured between the photoreceptor and the paper transport section. On the other hand, with the recent proliferation of office automation equipment, securing installation space has become a problem in small offices. For this reason, image forming apparatuses are also required to be downsized. However, if miniaturization is pursued, the developer container must also be miniaturized, and the demand for reducing the number of times developer is replenished cannot be met.

0004

[Means for Solving the Problems] The present invention provides an image forming apparatus that forms images by electrophotography, which includes a paper transport section having an overall length shorter than the width of the paper on an axis perpendicular to the paper transport direction. A developer container is provided in the vicinity of the photoconductor, and has a developer storage section that is rotatable and extends from the vicinity of the photoconductor to the outside of the axial end of the paper transport section.

[0005]

[Function] Since the developer container has a developer accommodating section extending on the axis of the paper transport section, it is possible to increase the developer accommodating capacity and reduce the frequency of developer replenishment. Become. Further, since the developer storage section can be arranged using the dead space on the axis of the paper transport section, it is possible to achieve downsizing.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained based on the drawings. 5 and 6 are longitudinal sectional front views. In the figure, 1 is a paper storage section. This paper storage section 1 stores A4 size paper 4.
A flat paper feeding body 2 that is slightly larger than the above, a mounting plate 5 held movably in the width direction of the paper 4 by a protrusion 3 formed at the bottom of the paper feeding body 2, and a mounting plate 5 that is movable up and down on the paper feeding body 2. It consists of a pressing plate 6 held at Guides 7 for supporting both side edges of the paper 4 are formed on both sides of the mounting plate 5. Further, although the pressing plate 6 holds the sheets 4 in a stacked state and is biased by a spring 8 in a direction away from the mounting plate 5, the guide 7 may be provided with a stopper 9 that contacts the top layer of sheets 4. This limits excessive upward movement. Furthermore, an electrical equipment compartment 10 is provided at the bottom of the paper feed main body 2.
The electrical equipment compartment 10 is provided with an electrical equipment case 11 and a circuit board 12 connected to the electrical parts housed in the electrical equipment case 11. A plurality of legs 14 that come into contact with a desk top are fixed to a base plate 13 that closes the bottom of the electrical equipment room 10. Further, a lid 15 is provided on the upper surface of the paper feed main body 2 so as to be openable and closable.

Further, a printing unit 16 is provided above the paper storage section 1. This printing unit 16 includes a case 18 rotatably held on both sides of the paper feed body 2 by a fulcrum shaft 17, a support frame 19 and a mounting plate 20 fixedly provided on the case 18, and a fulcrum shaft. 2
It has a cover 21 rotatably held by 1a. A developer container 22 containing developer is integrally formed on the support frame 19. The support frame 19 also includes a paper feed roller 23 which is a paper transport section.
A photoreceptor 24 whose outer diameter is set to approximately half the outer diameter of the paper feed roller 23, a developing roller 25, a regulating roller 26 that regulates the thickness of the developer layer, and a fixing roller 27. While being held rotatably, a motor (described later) for driving these rotating bodies is fixed.

The mounting plate 20 includes a charger 28 that applies a voltage to the photoreceptor 24 to charge the photoreceptor 24, and a charger 28 that irradiates the charged portion of the photoreceptor 24 with a light signal corresponding to an image signal. An exposure section 29 that forms an electrostatic latent image and a photoreceptor 24
An auxiliary brush 30 that evens out the developer remaining on the outer peripheral surface of the
and a static eliminator 30a that removes charges from the photoreceptor 24. The exposure section 29 is formed by arranging a large number of edge light emitting elements in a line. and,
The aforementioned photoreceptor 24, the developing roller 25 and regulation roller 26 in the developer container 22, the fixing roller 27 and the press roller 41, the charger 28, the exposure section 29, the auxiliary brush 30, and the static eliminator 30a. , and a transfer roller 39 form an image forming section 31.

A paper conveyance path 32 is formed between the case 18 and the cover 21, and the paper conveyance path 32 and the extension surface (paper feed path) of the uppermost layer of paper 4 on the press plate 6 are different from each other. , a plurality of ribs 34 connected by a reversing path 33 formed by a part of the outer circumferential surface of the paper feed roller 23, and for promoting the guiding action of the paper 4 through this reversing path 33.
is formed in the case 18. Further, a manual paper feed port 35 is formed at the end of the paper transport path 32 on the paper feed roller 23 side.

Furthermore, a paper guide surface 37 is formed on the toner cartridge 36 mounted in the developer container 22 , and a paper guide plate 38 facing the paper guide surface 37 is held by the cover 21 . The transfer roller 39 is rotatably held in the cover 21 in contact with the photoreceptor 24 . The paper guide plate 38 is formed of a leaf spring, and a pinch roller 40 and the press roller 41 are rotatably held at both ends thereof while being urged toward the case 18 side. As a result, the pinch roller 40 is brought into pressure contact with the paper feed roller 23, and the press roller 41 is brought into pressure contact with the fixing roller 27. Further, near the tip of the press plate 6 in the paper storage section 1, a lever 43 having a friction member 42 at the tip is biased clockwise by a spring 44 and is held rotatably about a support shaft 45. has been done. Thereby, the friction member 42 is brought into elastic contact with the outer peripheral surface of the paper feed roller 23. Further, a connector 46 for inputting power supply voltage, image signals, etc. is fixed to the case 18 of the printing unit 16, and a connector 47 connected to the circuit board 12 is provided in the paper storage section 1, These connectors 46 and 47 are connected by a cable 48.

Furthermore, the case 18 is provided with a stop lever 49. As shown in FIGS. 4 and 7,
This stop lever 49 is urged clockwise by a spring 50 and is rotatably held by a support shaft 51, and a stop shaft 52 facing the side edge of this stop lever 49
is erected on the side surface of the case 18. Further, a protrusion 53 is formed at the lower end of the stop lever 49 and comes into contact with the upper surface 2a of the paper feed main body 2. Here, FIG. 7 is a side view showing the relative relationship between the upper surface 2a of the paper feed main body 2 and the case 18 of the printing unit 16. That is, case 18
When pivoting upward about the fulcrum shaft 17, the relative position of the paper feeding main body 2 with respect to the upper surface 2a changes. Case 1
In case 1, the relative position of the top surface 2a with respect to 8 is L.
8 is located at the lower position and is in contact with the upper surface 2a of the sheet feeding main body 2. In this state, the rotational movement of the stop lever 49 is prevented by the contact between the upper surface 2a and the protrusion 53, and thereby the stop lever 49 is stopped. The upper part of the lever 49 is the manual paper feed slot 35.
stand out. When the relative position of the top surface 2a with respect to the case 18 is H, the case 18 is located at the upper position and is separated from the top surface 2a of the paper feed main body 2. In this state, the stop lever 49 is moved by the spring as shown by the imaginary line. It rotates clockwise due to the biasing force of 50, and its tip retreats below the manual paper feed port 35.

FIG. 8 is a front view showing the support structure of the case 18 of the printing unit 16 with respect to the paper feed main body 2. The fulcrum shaft 17 and the pin 54 are provided on the front and back sides of the case 18.
has been erected. Further, on the front and back sides of the paper feed main body 2, an L-shaped groove 55 for holding the fulcrum shaft 17 and a pin 5 are provided.
A notch 56 having an opening on the top surface into which the pin 54 is fitted is formed, and a hook 58 that is rotatably held on the support shaft 57 and latched to the pin 54 is provided. This hook 5
8 is biased in one direction by a spring 59,
Excessive rotational movement is prevented by the pin 60.

FIG. 9 shows the paper feed roller 2, partially in cross section.
FIG. 3 is a side view showing the support structure of No. 3; That is, a drive shaft 61 is provided that is connected to a motor via a spring clutch (not shown). The drive shaft 61 includes a hub 63 that is prevented from rotating by a pin 62, and a hub 63 that is fixed to the drive shaft 61 by a pin 62.
a hub 6 rotatably and slidably fitted in the axial direction of the hub 1;
4 and an elastic roller 65 that is rotatably fitted to one hub 63 and fixedly fitted to the other hub 64. The hub 64 is biased in one direction by a spring 66, and the hub 64 is biased in one direction by a spring 66.
A rotation transmitting portion 67 is formed on the opposing surfaces of the rotation transmitting portions 3 and 64 and is removably engaged with each other through a relationship between a protrusion and a groove. Further, a pair of rings 68 disposed on both sides of the paper feed roller 23 are fixedly fitted onto the drive shaft 61. These rings 68 are set to have an outer diameter smaller than the outer diameter of the paper feed roller 23, but a portion of the outer periphery is provided with a protrusion 6 that protrudes with a radius larger than the radius of the paper feed roller 23.
9 is integrally formed. These protrusions 69 function to press the top layer of paper 4 on the press plate 6 and separate the paper 4 from the paper feed roller 23 when the paper feed roller 23 is stopped. The spacing between the sides is set to match the width of the postcard.

Next, as shown in FIGS. 2 to 4, the support frame 19 is formed by joining a lower frame 19a with an opening at the top and an upper frame 19b with an opening at the bottom. The paper feed roller 23 and the photoreceptor 2 are attached to the side wall 19c formed in the
4, the developing roller 25, the regulating roller 26, and the fixing roller 27 are supported. Further, both sides of the support frame 19 are fixed to the bottom of the case 18 by screws 70. Further, the cover 21 has a protrusion 71 rotatably held on the fulcrum shaft 21a protruding from both sides of the support frame 19, and an operation panel 72 located on the upper surface. Further, the exposure section 29 is provided with a heat insulating plate 73. This heat insulating plate 73 is provided with a thermistor 74 that detects the temperature of the fixing roller 27, and a thermostat 75 that cuts off the connection between the heater of the fixing roller 27 and the power source when an abnormal temperature is reached. The static eliminator 30a is held on the lower surface of the tip of the heat insulating plate 73.

FIG. 1 is a plan view of the lower frame 19a,
FIG. 2 is a longitudinal sectional front view of the support frame 19 taken along line AA in FIG. As is clear from these figures, a recess 76 in which the paper feed roller 23 is positioned is formed in the center of the upper frame 19b and the lower frame 19a, and on both sides of this recess 76, the recess 76 is formed in the center of the upper frame 19b and the lower frame 19a. A developer storage portion 77 is formed so as to surround the drive shaft 61 and communicate with the developer container 22 . A widening portion 78 is formed on the wall surface of each of the developer storage portions 77 on the side of the recess 76 and is inclined so that the area and volume become larger toward the developing roller 25 . Furthermore, a motor 79 that drives the photoreceptor 24, the developing roller 25, the regulating roller 26, and the fixing roller 27 is provided, and the rotation of the motor 79 is intermittently controlled by the drive shaft 6 of the paper feed roller 23.
A clutch 80 that transmits the transmission to the support frame 19 is provided on one side of the support frame 19. Furthermore, the developer storage section 77
is provided with a stirring member 81 made of synthetic resin that is fixedly fitted to the drive shaft 61, and the outer periphery of these stirring members 81 has a tip edge in contact with the circular inner peripheral surface of the developer storage portion 77. The base of the flexible sheet 82 is welded.

FIG. 3 is a longitudinal sectional side view of the support frame 19 taken along line B-B in FIG.
is provided. As shown in FIG. 3, this detection lever 83 has a protrusion 85 that blocks the optical axis of the photosensor 84.
It is biased counterclockwise by a spring 86. Therefore, the paper 4 conveyed by the paper feed roller 23
When the leading edge of the detection lever 83 comes into contact with the upper end of the detection lever 83, the detection lever 83 rotates clockwise due to the conveyance force of the paper 4, and the photo sensor 8 responds to the rotational movement of the detection lever 83.
The advancing position of the paper 4 is detected by the detection signal 4. A stopper (not shown) is formed on the support frame 19 to abut against the protrusion 85 and prevent excessive movement of the detection lever 83 in the counterclockwise direction. Furthermore, wall surfaces 87 and 88 are formed in the developer container 22 to form a predetermined gap between them and the outer periphery of the developing roller 25.

In such a configuration, when printing using the paper 4 in the paper storage section 1, as shown in FIG. Maintain the state in which it is in contact with 2a. In this state, as described above, the tip of the stop lever 49 protrudes upward from the manual paper feed port 35, so that the paper feeding operation from the manual paper feed port 35 is prohibited. Then, when the paper feed roller 23 is driven clockwise, the sheets 4 stacked on the press plate 6 are separated one by one by the friction member 42 and pulled out, and are reversed toward the paper transport path 32 through the reversing path 33. . A photoreceptor 24 is attached to the paper 4 conveyed along this paper conveyance path 32.
The upper developed image is transferred by the transfer roller 39, and the transferred image is fixed by the fixing roller 27. The paper 4 with the image transferred in this way is discharged onto the top surface of the lid 15 of the paper storage section 1.

In FIG. 7, the stop lever 49 is biased by a spring 50, and its protrusion 53 presses the upper surface 2a of the paper feed main body 2, and the reaction force of the pressing force acts as an upward rotational force on the printing unit 16. However, when feeding paper from the paper storage section 1, as shown in FIG. Rotational movements are prevented.

Therefore, in FIG. 8, the spring 5
When the hook 58 is rotated counterclockwise against the biasing force of the spring 50 and removed from the pin 54, the stop lever 49 is rotated clockwise due to the biasing force of the spring 50, as shown by the imaginary line in FIG. Since the projection 53 presses the upper surface 2a of the paper feed main body 2, the reaction force causes the printing unit 16 to rotate upward about the fulcrum shaft 17. As a result, as shown in FIG. 6, a gap s is formed between the left upper surface of the paper feed main body 2 and the left lower surface of the case 18. In this state, the upper end of the stop lever 49 is retracted below the manual paper feed port 35, so that paper can be fed from the manual paper feed port 35.

As described above, since the developer container 22 has the developer storage portion 77 extending on the axis of the paper feed roller 23, the developer storage capacity can be increased and the developer can be replenished. It becomes possible to reduce the frequency. It is also possible to extend the period during which the developer once replenished into the developer container 22 is consumed until the life of the photoreceptor 24, thereby omitting the work of replenishing the developer in the middle and ending the life of the photoreceptor 24. At the same time, the support frame 19 on which the developer container 22 is formed and the photoreceptor 24 can be replaced as a unit. Further, since the developer accommodating portion 77 can be arranged using the dead space on the axis of the paper feed roller 23, it is possible to achieve miniaturization. Furthermore, since the paper guide surface 37 is formed on the upper surface of the toner cartridge 36 installed in the developer container 22, the number of paper guide members can be reduced.

In this embodiment, the printing unit 16 is arranged within the range of approximately the upper surface of the paper storage section 1. Further, it becomes possible to convey the paper 4 in the paper storage section 1 and the paper inserted from the manual paper feed port 35 using only one paper feed roller 23. Further, a photoconductor 2 is placed below the paper transport path 32.
4, the mounting position of the printing unit 16 can be lowered, and since the photoreceptor 24 is formed with an outer diameter that is approximately half the outer diameter of the paper feed roller 23, it is possible to lower the mounting position of the printing unit 16. The distance from the paper conveyance path 32 can be reduced, and each process unit for charging, development, transfer, etc. of the image forming section 31 can be easily arranged within a small space. Further, the paper 4 after printing can also be discharged onto the lid 15 of the paper feed main body 2. Therefore, the printing device can be extremely miniaturized.

Incidentally, the outer diameter of the paper feed roller 23 is approximately 20 mm.
The outer diameter of the photoreceptor 24 is set to about 10 mm. As a result, the length of the printing unit 16 in the paper feeding direction is about 70 mm, the height is about 30 mm, and the width corresponds to the width of A4 size paper 4, making it compact enough to be owned by an individual. Further, even if the size of the paper 4 to be used changes, only the width dimension of the printing unit 16 changes somewhat, and the height and length of the printing unit 16 are maintained within a certain dimension.

[0023]

Effects of the Invention The present invention provides an image forming apparatus that forms images by electrophotography, in which a paper transport section having a total length shorter than the width of the paper is rotatably provided on an axis perpendicular to the paper transport direction. Since a developer container having a developer accommodating portion extending from the vicinity of the photoconductor to the outside of the axial end of the paper transport section is provided near the photoconductor, the developer storage capacity can be increased. This reduces the frequency of replenishment of developer, and the dead space on the axis of the paper conveyance section can be used to arrange the developer storage section, making it possible to achieve downsizing. It has the effect of

[Brief explanation of the drawing]

FIG. 1 is a plan view of a lower frame.

FIG. 2 is a longitudinal sectional front view of the support frame taken along line AA in FIG. 1;

FIG. 3 is a longitudinal sectional front view of the support frame taken along line BB in FIG. 1;

FIG. 4 is an exploded perspective view showing the attachment structure of the support frame to the case.

FIG. 5 is a vertical sectional front view showing a state in which paper is fed from the paper storage unit.

FIG. 6 is a longitudinal sectional front view showing a state of paper being fed from the manual paper feed slot.

FIG. 7 is a side view showing the opening/closing operation of the manual paper feed slot by the stop lever.

FIG. 8 is a front view showing the support structure of the printing unit with respect to the paper storage section.

FIG. 9 is a longitudinal side view of the paper feed roller.

[Explanation of symbols]

22 Developer container 23 Paper transport section 24 Photoreceptor 77 Developer storage section

Claims (1)

[Claims] 1. In an image forming apparatus that forms images by electrophotography, a paper transport section having a total length shorter than the width of the paper is rotatably provided on an axis perpendicular to the paper transport direction, and the paper transport section is rotatably provided on an axis perpendicular to the paper transport direction. An image forming apparatus characterized in that a developer container is provided in the vicinity of the photoconductor, the developer container having a developer storage section extending from the vicinity to the outside of an end in the axial direction of the paper transport section.