JPH0346673A - electrophotographic equipment - Google Patents

Abstract

PURPOSE:To prevent the occurrence of troubles such as paper jamming caused by pulling out an image forming unit when the part of paper is inserted into an image forming case by providing detecting members for detecting paper in the front and back of a transfer means. CONSTITUTION:A paper sensors 53 and 54 for detecting the paper 38 are provided in the front and back, namely, the paper feeding side and the paper ejecting side of the transfer means 16. The paper sensor 53 is provided on the device main body 10 so as to face the paper 38 passing through on a paper guide 20, and the paper sensor 54 is provided on the device main body 10 so as to face the paper 38 passing through on the carrying belt 55 of the carrying device 23. When the existance of the paper 38 is detected by the paper sensors 53 and 54, the detection signal is sent to a CPU 56. As for the CPU 56, an electric signal is sent to a display panel 57 based on the detection signal, and it is displayed that the image forming unit 41 is inhibited from being pulled out. Thus, trouble such as paper jamming is prevented from occurring caused by pulling out the picture forming unit when the part of the paper is inserted into the picture forming case.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention applies to printers, copiers, facsimile machines, etc. that use lasers to repeatedly perform electrophotographic processes such as charging, writing, development, transfer, and cleaning, thereby producing images using electrophotography. The present invention relates to an electrophotographic device for recording.

BACKGROUND OF THE INVENTION This type of electrophotographic apparatus includes an image forming unit in which some electrophotographic process means such as charging, writing, developing, and transfer means are removably housed in an image forming case. There is an apparatus in which the image forming case is attached to the main body of the apparatus so as to be able to be pulled out. Therefore, the image forming unit can be appropriately pulled out from the apparatus main body to facilitate replacement and maintenance of the electrophotographic process means.

However, the problem that the invention aims to solve is that paper jams occur due to some reason,
Because the paper stops during paper feeding, a portion of the paper may enter the image forming case. Nevertheless, when the image forming unit is pulled out, the paper is torn. Then, when the sheet of paper to be transferred is sent again after that, it hits the torn pieces of paper, causing further inconveniences such as paper jams.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to prevent the conventional inconvenience caused by pulling out an image forming unit in an electrophotographic apparatus when a portion of paper has entered the image forming case. .

Means for Solving the Problems Therefore, the present invention provides, for example, a developing means 1 as well as an image carrier 2, as shown in the illustrated embodiments below.
5. Some of the electrophotographic processing means such as the transfer means 16 and the cleaning means 17 are assembled into an image forming case 40 which is removably provided in the main body 10 of the apparatus to form an image forming unit 41, and the image forming unit Paper 38 inside 41
When the paper 3 passes, the image on the image carrier 12 is transferred by the transfer means 16 provided in the image forming unit 4, and the image is transferred to the paper 3.
8, paper sensors 53 and 54 detect paper 38 before and after the transfer means 16.
It is characterized by comprising a detection member such as.

Function: If a portion of the paper 38 has entered the image forming unit 41, the detection member detects the paper.

Example Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the general configuration of a laser printer, which is an example of an electrophotographic apparatus. Reference numeral 10 in the figure is the main body of the apparatus, which is placed on an optional dedicated table 1. A drum-shaped image carrier (photoreceptor) 12 is provided in the center of the apparatus main body 10 and rotates clockwise in the figure. Around the image carrier 12, a charging means 13 and an optical writing means 4, which are electronic processing means, are arranged in order in the rotational direction.
・Developing means upper 5・Transfer means 16・Cleaning means 17
Place each of them.

On the other hand, on the right side of the apparatus main body 10 in the figure, paper feed cassettes 18 are removably loaded in the upper and lower directions. and,
Attaching portions of these paper feed cassettes 18, 18 are provided with a paper feed device 22 having paper feed rollers 19, 19, a paper guide 20, a pair of registration rollers 2, 21, and the like. On the other hand,
On the opposite side of the paper feeding device 22 across the transfer device 16 described above, a transport bag 23, a fixing device 24, a switching device 25, etc. are arranged in this order.

A face-down paper discharge path 26, a face-up paper discharge path 27, and a double-sided recording paper discharge path 28 extend separately from the switching device 25. The face-down paper discharge path 26 is connected to the main body 10 of the apparatus.
It also communicates with a discharged paper stack section 30 on the apparatus main body 10 via a discharge device 29 provided above. The face-up paper discharge path 27 leads to a face-up tray 31 provided on the side of the apparatus main body 10 so as to be openable and closable. Double-sided recording paper path 28
leads to the dedicated table 11.

By the way, the dedicated table 11 is provided with a paper reversing device 33 in communication with the above-mentioned double-sided recording paper discharge path 28, and
A paper refeeding device 34 is provided which connects the paper reversing device 33 to the paper feeding device 22 of the apparatus main body 10 described above. Also,
A large quantity paper feed cassette 35 is removably loaded on the right side of the dedicated table 1 in the figure. A large quantity paper feeding device 37 having a paper feeding roller 36 and the like is provided at the mounting portion of the large quantity paper feeding cassette 35.

4 However, when operating the laser printer now,
The paper feed roller 19 or the paper feed roller 36 is appropriately selected and driven to sequentially feed out the paper 38 from the cassettes 18 and 35.

On the other hand, while rotating clockwise in the figure, the surface of the image carrier 12 is sequentially charged by the charging means 3, and then laser light is irradiated by the optical writing means 14 to form an electrostatic latent image on the surface. Then, when the electrostatic latent image passes through the developing means 15, the electrostatic latent image is sequentially visualized. Then, by aligning the image and the resist, the aforementioned registration rollers 21 are driven, and the aforementioned paper 38 that has been in contact with the registration rollers 21 is sent out toward the image carrier 12. The image on the image carrier 12 is then transferred onto the paper 38 by the transfer means 16. After the transfer, the surface of the image carrier 12 is cleaned by the cleaning means 17.

On the other hand, the paper 38 is transferred to the fixing device 24 by the conveying device 23.
The image transferred thereto is fixed by the fixing device 24 thereof. When a large amount of paper 38 is to be discharged, or when it is desired to stack the sheets in page order, the sheets are passed through the face-down paper discharge path 26 to the discharge device 29 and then to the discharge stack section 30.
send it off to

When the paper 38 is thick paper such as a postcard, the switching device 25 switches the discharge direction, sends it out through the face-up paper discharge path 27, and stacks it face-up on the open face-up tray 31.

Furthermore, if you want to record on the back side, you can also use the switching unit W.
25, the discharge direction is switched, and the paper is conveyed through a double-sided recording paper discharge path 28, and guided to a paper reversing device 33 of a dedicated table earthwork.

Then, the sheet is reversed and conveyed again to the sheet feeding device 22 of the apparatus main body 10 through the sheet re-feeding device 34, and is again stopped against the registration roller 2. Then, it is recorded on the back side in the same way and is discharged onto the discharge stack section 30 or the face-up tray 3.

By the way, the illustrated laser printer includes an image carrier 12, a developing means 15, and a cleaning means 17, as shown in FIG.
is removably housed in the image forming case 40. Then, the upper transfer means 6 is attached to the lower side of the image forming case 40 so that it can be pulled out. Along with the image carrier 12, the developing means 15, the transfer means 16, and
A cleaning means 17 is provided in an image forming case 40, forming an image forming unit 41 as a whole. The image forming case 40 is provided with guide rails 4° and 40a in the length direction of both side walls. The guide rails 40a, 40a are slidably engaged with longitudinal guide members 42, 42 provided on the upper side of the apparatus main body. A handle 43 is provided on the front wall portion 4-Ob of the image forming case 40. Therefore, the image forming unit 41 is connected to the apparatus main body 10.
The front cover 44 of the device can be opened and pulled out to the front (front) side. This facilitates replacement and maintenance of the image carrier 2 and the electrophotographic processing means 15, 16, and F in the image forming unit 41.

Then, as shown in FIG. 3, a hole 40C is made in the front wall 40b of the image forming case 40, and a lock lever 45 is placed in the hole. The lock lever 45 has a plate shape, and has a proximal end with unevenness to form a grip half portion 45a. An upwardly recessed portion is provided near the tip to form an engaging portion 45b. When the lock lever 45 is attached to the image case 40, the engaging portion 45b is disposed below the lock pin 46 provided on the apparatus main body 10 side. The lock lever 45 is supported by a mounting shaft 47 and rotatably mounted on a mounting plate 48. The mounting plate 48 is fixed to the image forming case 40 with screws 49. Furthermore, as shown in FIG. 4, a toggle spring 50 is arranged on the mounting shaft 47, and its lower end is attached to the mounting plate 48, and the other end is attached to the lock lever.
45's engaging part 4.5 Attach to b side, lock lever 4
5 is normally rotated clockwise in the figure around the mounting shaft 47. On the other hand, the lock pin 46 on the device main body 10 side
is held, for example, by a bracket 52 screwed into the side plate 5 of the main body 10 of the apparatus. Then, as shown in FIG. 4, the engaging portion 45b of the lock lever is engaged with the lock pin 46, and the image forming unit 41 is locked onto the main body O of the apparatus.

Furthermore, the illustrated laser printer, as shown in FIG.
Paper sensors 53 and 54 are provided as detection members for detecting the paper 38 before and after the transfer means 16, that is, on its paper feed side and paper discharge side. The paper sensors 58-3 and 54 are light reflective sensors. One paper sensor 53 is provided in the apparatus main body 10 to face the paper 38 passing over the paper guide 20. The other paper sensor 54 is similarly provided on the main body O of the apparatus so as to face the paper 38 passing over the transport belt 55 of the transport device 23 . And paper sensor 5
3.54 detects the presence of the paper 38, and sends the detection signal to the CPU 56, as shown in FIG. CPU5
6 is a display panel 5 that displays an electrical signal based on this detection signal.
7, and a display indicating that the image forming unit 41 is prohibited from being pulled out is displayed on the display panel. And display panel 5
7 is a discharged paper stack section 30 as shown in FIG. 2, for example.
It is provided on the operation display section 30a provided on the front side of the screen.

For example, during maintenance of the image forming unit 41, the front cover 44 of the apparatus main body 10 may be damaged as shown in FIG.
When opened, the operation of the main body 10 of the device stops. Then, the paper feed also stops, the paper 38 enters the image forming case 40, and the transfer means 16 and the registration roller 2
1 and 21 or the fixing device 24, either one of the paper sensors 53 and 54 detects this. Then, the CPU 56 sends an electric signal to the display panel 57 based on the paper detection signal, and displays on the display panel 57 a message prohibiting the image forming unit 4 from being pulled out. Therefore, the operator refrains from opening the image forming unit 1-41 after seeing this display. Therefore, after removing the remaining paper, the image forming units 1 to 4 are pulled out. To draw out the image forming unit 41, as shown in FIG.
This is done by releasing the engagement with the lock pin 46.

Now, in the illustrated embodiment described above, when the paper sensors 53 and 54 detect the presence of the paper 38, the display panel 57 displays a message prohibiting the drawing out of the image forming unit 41. At the same time, the image forming unit 1-41 is locked to the apparatus main body 10 to prevent its removal.

In that case, for example, as shown in FIG. 4, a stopper 60 is provided above the image forming case 40. The stopper 60 is
A hook portion 60a projecting downward in the figure is formed at one end thereof. Then, it is supported by a mounting shaft 61 and rotatably mounted on the main body of the apparatus.

One end of the spring 62 is attached to the other end of the collar 60. The other end of the spring 62 is attached to the bracket 52. Thus, the spring 60 is always given the habit of rotating counterclockwise in the figure about the mounting shaft 61. Further, a plunger 63a of a solenoid 63 is connected to the other end of the spring 60.

The solenoid 63 is attached to the side plate 51 of the device main body 10 and electrically connected to the CPU 56 as shown in FIG.

For example, during maintenance, when the paper sensors 53 and 54 detect the paper 38 in the same manner as described above, the fifth
As shown in the figure, the CPU 56 sends an electric signal to the solenoid 63 based on the detection signal. Then, the solenoid 63 is actuated by the electric signal, and as shown in FIG. 4, the plunger 63a is sucked inside and the other end of the stopper 6o is pulled up. Then, the collar 60 rotates clockwise in the figure against the spring 62, hooking the hook portion 60a onto the upper end of the imaging case 40 and locking the imaging unit 4 so that it cannot be pulled out. do. Therefore, if the operator overlooks the display panel 57 displaying the prohibition of bow extension and tries to pull out the image forming unit, the lock lever 45
Even if the locked state is released, it is possible to prevent the image forming unit 4 from being pulled out.

After that, the paper 38 inside the image forming unit 41 is removed. Then, the paper sensors 53 and 54 detect that there is no paper 38, and the CPU 56 sends an electric signal to the solenoid 63 based on the detection signal. Then, solenoid 6
3 stops the operation and releases the suction of the plunger 63a. Then, the collar 60 rotates counterclockwise in the figure to remove the hook portion 60a from the image forming case 40, allowing the image forming unit 41 to be pulled out.

By the way, in the illustrated embodiment described above, the light reflection type paper sensors 53 and 54 are used as the detection members, but the paper is not limited to this, and various detection members such as light transmission type sensors and microswitches can be used to detect the paper. It may be configured to do so. In the illustrated embodiment described above, the detection members are provided in the paper feeding device 22 and the conveyance device 23, respectively, but the detection members are not limited to these locations as long as they are provided before and after the transfer means 6.

In addition, in the illustrated embodiment described above, a case where the present invention is applied to a laser printer is shown. However, it is not limited to laser printers.
The present invention can be similarly applied to other laser recording devices such as laser copying machines and laser facsimile machines. Further, the present invention is not limited to laser recording devices, but can be similarly applied to other electrophotographic recording devices.

Effects of the Invention Therefore, according to the present invention, since the detection member for detecting the paper is provided before and after the transfer means, even when a part of the paper has entered the image forming case, the paper can be detected. However, it is possible to prevent various inconveniences such as paper jams from occurring by pulling out the image forming unit.

[Brief explanation of drawings]

FIG. 1 is an overall schematic diagram of a laser printer which is an embodiment of the present invention, FIG. 2 is a perspective view showing the replacement of electrophotographic processing means in this laser printer, and FIG. 3 is a diagram showing the locking mechanism of the image forming unit. FIG. 4 is a schematic sectional view of the locking mechanism, and FIG. 5 is a control block diagram when the paper sensor detects paper. ]0...Device body work 6...Transfer means 38...Paper 40...Image forming case 41...Image forming unit

Claims (1)

[Claims] Some of the electrophotographic process means along with the image carrier,
An image forming unit is constructed by assembling the image forming case into an image forming case which is provided in a drawable manner in the main body of the apparatus, and when a sheet of paper passes through the image forming unit, the image on the image carrier is transferred by a transfer means provided within the image forming unit. An electrophotographic apparatus for recording on paper by transferring the image, the electrophotographic apparatus comprising a detection member for detecting the paper before and after the transfer means.