JP2003149890A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus in which jam processing is facilitated by preventing a recording medium from being ripped when jamming is generated. SOLUTION: When the recording medium exists in between a paper feeding cassette 22 and a carrying roll 38 (or a resist roll 40), a carrying sensor 84 is turned on regardless of whether there is any jamming or not. In this case, a solenoid 80 is turned on and a pushing member 82 is lowered and fit into an recessed part 22a. Therefore, the paper feeding cassette 22 cannot be pulled out from a box body 12.

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 for forming an image on a recording medium such as recording paper.

[0002]

2. Description of the Related Art An electrophotographic image forming apparatus for forming an image on a recording medium by using a powdery developer (toner) as an output device of a computer or a workstation, or an image by ejecting ink on the recording medium. An inkjet type image forming apparatus for forming an image is known. Such an image forming apparatus includes a type in which a paper feed cassette on which a large number of recording media are stacked is detachably provided.

This type of image forming apparatus is equipped with a transport mechanism for transporting a large number of recording media loaded in a paper feed cassette one by one in a predetermined transport direction. This transport mechanism is, for example, a paper feed roller that feeds (sends out) a plurality of recording media loaded in a paper feed cassette while pressing the recording media from above, or a recording paper fed from a paper feed roller. It is composed of a pair of transport rollers and the like that transports while sandwiching the medium. Further, in the main body (housing) of the above-mentioned type image forming apparatus, an openable and closable door for covering the transport mechanism is generally formed.

By the way, in the image forming apparatus of the type described above, a paper jam (jam) may occur between the paper feed cassette and the transport mechanism. Therefore, there is a configuration in which the pair of conveyance rollers are separated from each other by opening the door so that the recording medium having the paper jam can be easily removed.

[0005]

However, when a jam occurs, the paper feed cassette may be pulled out from the main body before the door is opened. In this case, when the jammed recording medium is pressed against the paper feed roller and is also sandwiched by the pair of transport rollers, the recording medium is torn off by pulling out the paper feed cassette. If the recording medium is torn in this way, the jam processing will take time and effort.

In view of the above circumstances, it is an object of the present invention to provide an image forming apparatus that prevents the recording medium from being torn when a jam occurs and facilitates the jam processing.

[0007]

An image forming apparatus of the present invention for achieving the above object is provided with a housing having a predetermined shape and a large number of recording media loaded and detachably mounted on the housing. A paper feed cassette, a carrying mechanism for carrying the recording media stacked in the paper feed cassette one by one in a predetermined carrying direction, and an openable and closable door formed in the housing to cover the carrying mechanism. In an image forming apparatus for forming an image on a recording medium conveyed from the paper feeding cassette by the conveying mechanism, (1) when the recording medium is jammed while the conveying mechanism conveys the recording medium, And a lock unit for preventing the paper feed cassette from being pulled out from the housing.

Here, the locking means includes (2) a solenoid attached to the casing, and (3) an extruding member attached to the solenoid that is pushed out when the solenoid is on. (4) A recess formed in the paper feed cassette into which the pushed-out push-out member fits may be provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus of the present invention will be described with reference to FIGS.

FIG. 1 is a perspective view showing a digital copying machine which is an embodiment of the image forming apparatus of the present invention. Figure 2
It is a schematic diagram which shows the internal structure of the digital copying machine of FIG.
FIG. 3 is a perspective view showing a paper feed cassette, a solenoid, and the like.

The copying machine 10 has a housing (image forming apparatus main body) 12 in which a plurality of parts for reading an image recorded on a document are incorporated. On the top surface of the copying machine 10 is arranged a rectangular parallelepiped original document pressure plate 14 which can be opened and closed. An optical device (not shown) in which a well-known optical system (not shown) is incorporated is arranged under the document pressure plate 14. This optical device is equipped with a light source LED (not shown) and the like. A document table glass 18 on which a document is placed is arranged on the upper surface (upper wall) of the optical device. A laser scanner 16 is arranged below the optical device.

An operation panel 20 for inputting the number of copies and the like is arranged on the front side of the housing 12 with respect to the original pressure plate 14. In addition, in the lower part of the housing 12,
A paper feed cassette 22 accommodating a plurality of cut sheets is mounted in the housing 12 so that it can be freely taken in and out (removably).
The right side wall of the housing 12 is formed with a door 24 that is opened at the time of jam processing or the like. The door 24 is closed when the copying machine 10 is used, and covers a transport mechanism described later. Further, a paper discharge tray 26 on which a recording medium having an image formed thereon is discharged and stacked is formed on the left side portion of the housing 12.

A procedure for forming an image by the copying machine 10 will be described with reference to FIG.

When forming an image with the copying machine 10, the original pressure plate 14 is opened, and the original is placed on the upper surface of the original glass 18 so that the image side faces down.
Hold with 4 to fix. Next, by pressing an operation button or the like on the operation panel 20, the image recorded on the document is read by the optical system incorporated in the optical device. The read image is converted into a digital signal, and this digital signal is transmitted to the laser scanner 16.

The signal transmitted to the laser scanner 16 is converted into laser light, and this laser light is applied to the photosensitive drum 30. The photosensitive drum 30 is uniformly charged by the charger 32, and the photosensitive drum 3 irradiated with the laser light is charged.
At 0, an electrostatic latent image is formed. This electrostatic latent image is developed with the developer supplied from the developing roller 34 to form a developed image.

On the other hand, a recording medium such as recording paper is fed from the paper feed cassette 22 by the paper feed roller 36 in the direction of arrow A (the paper feed direction, which is an example of the carrying direction in the present invention). Since the recording medium sent out from the paper feed cassette 22 is conveyed in the direction of arrow A, it is conveyed while being reversed. The recording medium is a pair of conveyance rollers 38.
It is conveyed while being sandwiched by and reaches the registration roller 40. The recording medium is conveyed to the transfer device 42 by the registration rollers 40.

In the transfer device 42, the developed image on the photosensitive drum 30 is transferred to the conveyed recording medium. The recording medium on which the developed image is transferred is conveyed to the fixing device 46 by the conveying device 44. The fixing device 46 is provided with a fixing roller 46 a and a pressure roller 46 b.
The recording medium is conveyed while being sandwiched between a and 46b, and the developed image is fixed on the recording medium. The recording medium on which the developed image is fixed in this manner is discharged by the paper discharge roller 48 and stacked on the paper discharge tray 26. The copying machine 10
A power supply for driving various components and an electrical component board 50 on which electrical components are mounted are also incorporated.

The structure of the paper feed cassette 22 and its surroundings will be described with reference to FIGS.

The paper feed cassette 22 includes a cassette pocket 60 having a rectangular bottom wall 62 and an open top surface, and a rectangular middle plate 70. One side portion 72 of the middle plate 70 on the downstream side in the sheet feeding direction (direction of arrow A) extends in the orthogonal direction orthogonal to the sheet feeding direction, and can move freely from and away from the bottom wall 62 of the cassette pocket 60. The orthogonal direction is also the width direction of the recording medium loaded on the intermediate plate 70. Also, one side 72
A compression coil spring 76 for urging the one side portion 72 upward to separate it from the bottom wall 62 of the cassette orchest 60 is arranged below.

On the other hand, the other side portion 74 of the intermediate plate 70 on the upstream side in the sheet feeding direction is attached near the bottom wall 62 so as to be freely rotatable within a predetermined angle range. When the one side portion 72 is raised by the compression coil spring 76, the middle plate 70 is inclined upward from the other side portion 74 toward the one side portion 72. As a result, a large number of recording media stacked in the paper feed cassette 22 are fed from above the paper feed roller 3
While being pressed by 6, the sheets are fed (fed out) one by one in the direction of arrow A. The recording medium thus fed is conveyed while being sandwiched between the pair of conveying rollers 38, as described above. Here, the paper feed roller 36, the transport roller 38, and the like constitute the transport mechanism referred to in the present invention. The paper feed roller 36 and the transport roller 38 are attached to the housing 12.

The feeding direction of the paper feed cassette 22 (arrow A
The solenoid 80 is fixed as shown in FIG. 3 at a position slightly deviated to the side from the downstream side portion in the direction). The solenoid 80 is attached and fixed to the inner wall of the housing 12 (see FIG. 2). A rod-shaped extruding member 82 is fixed to the solenoid 80, and the extruding member 82 moves in the vertical direction (arrow B direction) as the solenoid 80 is turned on and off.

In the portion of the paper feed cassette 22 located below the pushing member 82, there is formed a recess 22a into which the pushing member 82 is fitted when it is lowered. Further, in a portion of the conveyance path between the paper feed roller 36 and the conveyance roller 38 (a portion slightly upstream of the conveyance roller 38 in the conveyance direction), conveyance for detecting the recording medium conveyed from the paper feed cassette 22 is performed. A registration sensor 85 is arranged in the immediate vicinity of the sensor 84 and the registration roller 40, a separation sensor 86 is arranged in the downstream of the transfer device, and a paper discharge sensor 87 is arranged in the vicinity of the paper discharge roller.
The structure of these sensors is a well-known structure, and is composed of a photo sensor or the like. These sensors detect the presence / absence of a recording medium, and this detection method determines that there is a jam (paper jam) when the recording medium being conveyed remains in the presence state for a predetermined time. . When it is determined that a jam has occurred, the conveyance of the recording medium is stopped urgently.

When the conveyance of the recording medium is urgently stopped due to a jam, the solenoid 80 is turned on when the conveyance sensor 84 detects the recording medium (when it is on). When the solenoid 80 is turned on, the pushing member 82 is lowered and fits into the recess 22a. Therefore, the paper feed cassette 22 cannot be pulled out (cannot be pulled out) from the housing 12 when the transport sensor 84 is on. On the other hand, when the conveyance of the recording medium is urgently stopped due to a jam, and the conveyance sensor 84 does not detect the recording medium (when the recording medium is off), the solenoid 80 is also off. When the solenoid 80 is off, the push-out member 82 moves up and comes out of the recess 22a. Therefore, when the transport sensor 84 is off, the paper feed cassette 22 can be pulled out (drawn) from the housing 12.

In the copying machine 10, a paper jam (jam) may occur between the paper feed cassette 22 and the transport roller 38 (or the registration roller 40). In this case, the jammed recording medium or the recording medium to be subsequently conveyed is held by the pair of conveying rollers 38 (or registration rollers 40) while being pressed against the paper feed roller 36. Therefore, assuming that the paper feed cassette 22 is pulled out from the housing 12 in this state, the jammed recording medium or the recording medium to be conveyed next is torn off. When the recording medium is torn in this way,
It takes time and trouble to clear the jam.

However, in the copying machine 10, the paper feed cassette 2
When the recording medium is present between the sheet 2 and the conveyance roller 38 (or the registration roller 40), the conveyance sensor 84 is turned on regardless of whether or not there is a jam. In this case, as described above, the solenoid 80 is turned on, and the pushing member 82 is lowered and fits in the recess 22a.
Therefore, the paper feed cassette 22 cannot be pulled out from the housing 12. As a result, the jammed recording medium or the recording medium to be conveyed next is not torn off. The jam processing is performed by opening the door 24 (see FIG. 2), and when the recording medium is removed and the conveyance sensor 84 is turned off, the solenoid 80 is also turned off.

Here, in the present embodiment, the solenoid 80 or the like as the locking means is provided on the back side of the paper feed cassette 22, but
The locking means is provided on the front side of the housing, and as shown in FIG. 4, the recess 23 into which the pushing member is fitted on the front side of the sheet feeding cassette 23.
You may form a. At this time, a display window 23b may be provided on the front surface of the paper feed cassette 23 to display "undrawable" in conjunction with the downward movement of the pushing member.

[0027]

As described above, according to the image forming apparatus of the present invention, even if a paper jam occurs between the paper feed cassette and the transport mechanism, the locking means pulls the paper feed cassette out of the housing. I try not to. Therefore, when a paper jam occurs between the paper feed cassette and the transport mechanism, the paper feed cassette is not pulled out from the housing and the jammed recording medium or the like is not torn off. As a result, the recording medium will not be torn when the paper is jammed, and thus the jam processing will not be troublesome.

Here, the locking means includes a solenoid attached to the casing, an extruding member attached to the solenoid that is extruded when the solenoid is on, and the extruding push member. When the member is provided with a recess formed in the paper feed cassette, the careless pulling out of the paper feed cassette can be reliably prevented with a simple structure.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a digital copying machine which is an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a schematic diagram showing an internal structure of the digital copying machine of FIG.

3 is a perspective view showing a paper feed cassette, a solenoid, and the like of the digital copying machine of FIG.

FIG. 4 is a perspective view showing another embodiment.

[Explanation of symbols]

10 Copier 12 cases 22 Paper feed cassette 22a recess 36 paper feed rollers 38 Conveyor rollers 80 solenoid 82 Extruded member 84 Transport sensor

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H072 AA02 AA12 AA13 AA14 AA24                       AB01 AB25 BA03 EA11 JA02                 3F343 FA01 FB01 FC08 FC26 GA01                       GB01 GC01 GD02 HB03 HC26                       HC27 HC28 JA01 KB03 LA04                       LA13 LC16 LC20 LC24 MA03                       MA13 MA14 MA15 MA56 MB10                       MC20 MC26 MC27

Claims (2)

[Claims] 1. A housing having a predetermined shape, a paper feed cassette in which a large number of recording media are loaded and detachably mounted in the housing, and one recording medium loaded in each of the paper feed cassettes. A transport mechanism for transporting in a predetermined transport direction, and an openable / closable door formed in the housing to cover the transport mechanism,
In an image forming apparatus for forming an image on a recording medium conveyed from the paper feeding cassette by the conveying mechanism, the recording medium causes a paper jam in the vicinity of the paper feeding cassette while the recording medium is being conveyed. At this time, the image forming apparatus is provided with a lock unit for preventing the paper feed cassette from being pulled out from the housing. 2. The locking means is a solenoid attached to the casing, and is pushed out when the solenoid is on.
The image forming apparatus according to claim 1, further comprising: an extruding member attached to the solenoid; and a recess formed in the sheet feeding cassette into which the extruding member extruded is fitted. apparatus.