JPH0466963A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent deviation of position of an image carrier and an actuating means by separating the image carrier and image carrier actuating means more than a specified distance interlocking with a release operation of restraining of a first box body and a second box body. CONSTITUTION:When an opening/closing lever 21 is pressed in the direction C, the opening lever 21 is rotated with the lever shaft part 10d as a rotary shaft, a hook part 21a is removed from a part 1c of the main body machine box 1 of the first machine box, and the restraining of the main body machine box 1 is released. At the same time, a shaft of a transfer roll 2a of a transfer device 2 is pressed down by a part 21b of the opening lever 21. The distance between a center of a drum 3 and a center of a transfer roll 2a, the actuating means, is made greater than the distance at the time of image formation interlocking with the release operation of a restraining means restraining this machine box 1 and a front box body 20 of the second machine box, and the surface f the drum 3 and the surface of the roll 2a are separated. It is the same for closing and restraining of the box bodies 1 and 20, the deviation in position between the image carrier and the actuating means is prevented and an image of a good quality is formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to sorting from a paper feeding section to an image forming means section according to an appropriate image forming principle and method such as electrophotography, electrostatic recording method, magnetic recording method, etc. Material (cut note material (sheets) such as transfer paper, electrostatic recording paper, electrofax paper, photosensitive paper, printing paper, etc.) is fed to a single sheet and transferred to the surface of the fed sorting material (indirect) method. Alternatively, the present invention relates to an image forming apparatus such as a copying machine or a printer that directly forms a target image.

[Prior Art] FIG. 5 is a schematic diagram of examples of image forming apparatuses as described above, and all of them are laser beam printers (LBP) using transfer type electrophotography.

Reference numeral 100 denotes a main body printer housing, in which the following image forming means devices are housed. That is, 101 is a rotating drum type electrophotographic photosensitive member (hereinafter referred to as a drum), which is rotated clockwise as indicated by an arrow around a central support shaft at a predetermined circumferential speed. During the rotation process of the drum 101, the outer peripheral surface of the drum 101 is uniformly charged with positive or negative charges by a primary charger 102, and then an electronic computer/word processor (not shown) is outputted from a laser scanner 103. An electrostatic latent image of the target image is formed by scanning exposure with a laser beam L that is modulated in accordance with time-series electric pixel signals of the target image inputted from an image reading device or the like. 103a
indicates a mirror that deflects the output laser L from the scanner 103 to the scanning exposure section of the tram 101. The latent image formed on the drum surface is then visualized by a developing device 104 as a transferable developer image (toner image).

On the other hand, among the stacked and stored sheet materials P in the sorting material cassette 106 whose leading end is inserted into the paper feed port 105 provided on the right side of the printer main body machine casing 100, only one of the uppermost sheet materials is 1. One sheet is separated by a feed roller 107 and a separating claw 108, which are driven intermittently, and fed into the printer.The sheet passes through a note path 109 and is placed at the nip of a pair of register rollers 110, which are currently not rotating. The sheet is once stopped from being received, and then passed through a sheet path 111 by a register roller 110 which is driven to rotate at a predetermined timing synchronized with the rotation angle of the drum 101, and is placed facing the drum 101 and its lower surface. The image transfer unit 113 is conveyed at the same speed as the rotational peripheral speed of the hetram 101 between the transfer charger 112 and the transfer charger 112 . register roller pair 1
Reference numeral 10 serves to adjust the timing for feeding the sheet material to the transfer unit 113 and to correct the skew of the sheet material.

The sheet material conveyed to the image transfer section 113 is transferred to the drum 101
The toner image on the side of the drum 101 is sequentially transferred, separated from the side of the drum 101, and transferred to the fixing device 115 by the conveying device 114.
The image is conveyed to the printer and passes through the fixing device while undergoing image fixation.

The sheet material coming out of the fixing device 115 is conveyed by a paper discharge roller 117 and discharged out of the device.

Drum 101 after toner image transfer to feeding sheet material
The cleaning device 128 removes residual contaminants such as residual transfer toner and paper dust from the surface to make it a clean surface.
Further, the electrical memory is erased by uniform exposure using a static eliminating lamp 129, and the image is repeatedly formed.

The printer of this example is a so-called process cartridge removable type printer, which includes a tram 101, a blower 102, and a developer 10.
4. The four cleaning devices 128 are assembled into a common cartridge rerun housing in a predetermined mutual positional relationship to form a process cartridge 130 that can be freely attached to and removed from the inside of the printer.

In addition, a so-called clamshell type or alligator type device opening structure is used to open the inside of the printer for maintenance inside the printer, attaching and detaching the process cartridge 130, taking out and removing jammed sheet material in the sheet material conveyance path (sheet path), etc. The configuration is adopted. In other words, the printer body is connected to the process cartridge 13 with a nearly horizontal sheet path in the printer extending from the sorting material feeding section on the right side of the printer body to the paper ejection roller 117 on the left side of the printer body.
0 and the upper half including the laser beam scanner 103, etc.
The hinge support shaft 131 has a two-part structure with a lower half containing a sheet material cassette 106, a transfer charger 112, a conveying device 114, a fixing device 115, etc., and an upper half half is provided on the left side of the lower half. The printer is opened at the center as shown by the two-dot chain line and rotated in the direction of the arrow X, leaving the inside of the printer in a wide open state.

This opening facilitates maintenance inside the printer, attachment/detachment of the process cartridge 130, and operation of taking out and removing jammed sheet material.

Similarly, in an image forming apparatus having a substantially vertical sheet path,
As shown in FIG. 6, in the printer main body 250, the front casing 220 located on the front side of the main body casing 201 is closed against the front surface of the main body casing 201 around the horizontal hinge axis 290 at the lower side of the main body, and rotates when opened. It is movably mounted and can be left wide open across the substantially vertical seat path.

[Problem that the invention is trying to solve]

However, in the conventional example described above, the transfer devices 112 and 207 are not positioned with respect to the drums 101 and 203 of the process cartridges 130 and 230 in the X direction when the devices are opened and closed, and there is a drawback as shown below.

(1) Increased transfer voltage and current and poor separation due to parallelism and misalignment of the process cartridge drum and transfer device. In particular, in the case of the transfer roller 207 shown in FIG. 6, the transfer/separation performance deteriorates due to bending of the sheet material due to the roller.

(2) Increased costs due to additional adjustments and improved parts accuracy to prevent the defects mentioned in (1).

(3) When the transfer device is attached to the drum side, it is inconvenient to deal with jams, etc.

[Purpose of the invention]

The present invention has been made in view of the above points, and provides an image forming apparatus that prevents misalignment between an image bearing member and acting means such as a transfer device that acts on the image bearing member, and forms a good image. The purpose is to provide.

[Structure of the invention]

In order to achieve the above object, according to the present invention, a first housing and a second housing that can be opened with respect to the first housing can be divided, and include an image carrier and an image for performing image formation. an action means that is provided at a predetermined distance from the image carrier and acts on the image carrier; a locking means that locks the first casing and the second casing;
The image forming apparatus has a releasing means for releasing the locking by the locking means, characterized in that the image carrier and the acting means are separated from each other by more than the predetermined distance in conjunction with the releasing operation by the releasing means. That is.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

An embodiment of the image forming apparatus of the present invention is shown in FIGS. 1 to 4. 1 to 3 are partial cross-sectional views illustrating a release mechanism of a transfer device applicable to the image forming apparatus of the present invention, and FIG. 4 is a general cross-sectional view of the image forming apparatus of the present invention.

First, the entire image forming apparatus will be explained with reference to FIG. 1.
is a printer main body housing, and inside the main body machine case there are necessary image forming process equipment as an image forming means, namely, a rotating tram type electrophotographic photoreceptor 3 (hereinafter referred to as tram) which is an image carrier, and the tram surface. Charging device 5 as uniform charging means
, a laser beam scanner 6, a developing device 7, and a cleaning device 4, and images are formed using a transfer device 2 provided in a front casing 20. The above charging device 5,
The scanner 6, the developing device 7, the cleaning device 4, and the transfer device 2 are acting means that act on the image carrier.

Explaining according to the sheet material conveyance path, the sheet material is first conveyed upward from the cassette feeder 60, enters the downward entrance portion 80 as the first paper feed port on the bottom side of the printer body 50, and is supplied into the printer body 50. The sheet material is conveyed between the pair of registration rollers 8, between the drum 3 and the transfer roller 2a of the transfer device 2, between the pair of fixing rollers of the fixing device 11, and between the pair of paper discharge rollers 13, and then delivered to the printer body. It is discharged onto the tray 14 on the upper surface.

On the other hand, the stacked sheets on the paper feed tray 22 serving as the second paper feed section are fed by a sheet material separation and feeding assembly 9 that separates and feeds the sheets one by one, and are sent to a pair of registration rollers 8.
After passing through the same conveyance path as described above, it is discharged onto the tray 14. In this way, the sheet material conveyance path extends within the printer body from the bottom plate side of the printer body case to the top plate side near the front case (the right end surface in the drawing) on the front side of the printer main body case l. It has a vertical seat path.

Based on the print start signal, the drum 3 is rotated at a predetermined circumferential speed in the counterclockwise direction of arrow A, and the rotating drum surface is positively or negatively charged by the charging device 5, which is a charging roller to which a voltage is applied. The electrostatic latent image of the target image information is formed by being uniformly charged to the polarity of , and then receiving scanning exposure of the laser beam L outputted from the laser scanner 6 in accordance with the image signal. The formed latent image is then developed as a toner image by the developing device 7.

On the other hand, in the cassette feeder 60, the paper feed roller 67 is driven to rotate, and the uppermost sheet of the sheet materials P stacked on the middle plate 62 is fed by the separation claw 64, and the uppermost sheet is fed by the separation claw 64, The paper is introduced into the printer main body from the downward entrance portion 80 as the first paper feed port on the bottom surface of the printer, and is conveyed from the bottom to the top along the above-mentioned substantially vertical sheet path.

In other words, the pair of registration rollers 8 are rotationally driven in the direction of the arrow.
between the tram 3, which is guided by kites 7a and 2f provided on the side of the sheet material conveyance path between the developing device 7 and the holder 2e of the transfer device 2, and the transfer roller 2a of the transfer device 2, which comes into contact with the drum 3. The toner images formed and carried on the surface of the drum 3 are sequentially transferred by passing between the drum 3 and the transfer roller 2a to which a voltage is applied by a power source.

At this time, a high voltage current is applied to the transfer roller 2a by a high voltage device (not shown) through the power supply plate I2. A sheet material serving as a transfer material that has passed between the drum 3 and the transfer roller 2a and has received the image transfer is separated from the surface of the drum 3 and introduced into the fixing device 11 by a guide, where the fixing roller pair is driven to rotate in the direction of the arrow. The image is fixed by passing through the gap, and the sheet is discharged along the kite, and is conveyed onto a tray 14 serving as a sheet discharge section through a pair of sheet discharge rollers 13 which are rotationally driven in the direction of the arrow.

The front casing 20 serves as a cover before opening and closing the printer main body 50 and is attached to the front surface of the main body casing 1 around a horizontal hinge shaft 90 at the lower side so that it can be opened and rotated. The image forming process equipment on the front housing 20 side with respect to the above-mentioned substantially vertical sheet path in the printer main body 50, that is, the sorting material single sheet separation and feeding assembly 9, the transfer device 2, the fixing device 11, etc. are located under the front cover 10. The assembly is supported in a predetermined arrangement relationship on the back side of the image forming process equipment on the side of the main body machine housing with the almost vertical sheet path as a boundary, namely, a pair of registration rollers 8, a tram 3, a racer scanner 6, The charging device 5, the developing device 7, the cleaning device 4, the paper ejection roller pair 13, the drive source, the main electrical components of the control system, etc. are assembled in the main body machine casing 1 in a predetermined arrangement relationship.

FIG. 1 shows the position of the transfer device 2 during image formation in this image forming apparatus.
The transfer roller 2a is positioned and supported by the bearing 1b with respect to the main body machine casing 1, and the center of the tram 3 and the center of the transfer roller 2a are maintained at a predetermined distance. Furthermore, when the front housing 20 is in the closed state shown in FIG. It is locked in the locking part 1c of the main body machine casing 1 and stably held.

In FIG. 1, the transfer roller 2a of the transfer device 2 has a bearing 2b.
Through this, the pressure plate 2c, which is rotatable with respect to the rotation axis 10a of the front cover 10, and the spring hook of the front cover 10 apply a pressure force in the A direction by the force in the B direction of the pressure spring 2d located between the portion 10c. The surface of the drum and the surface of the transfer roller are in contact with each other. The pressing force of the transfer roller 2a against the drum 3 in the direction A is applied directly to the drum 3 or to the bearing 1b of the main body machine housing 1 to ensure a stable transfer area and conveying force between the tram 3 and the transfer roller 2a. There is.

In this embodiment, the printer includes a drum 3, a charging device 5 acting on the drum, a developing device 7, a cleaning device 4, etc. among the image forming process equipment, which are assembled in a common cartridge housing with a predetermined mutual relationship. The process cartridge 30 is removably attached to the printer body 5 of the process cartridge 30.
When attaching and detaching the jammed sheet material within the substantially vertical sheet path,
Or, when performing maintenance etc. inside the printer, use the front housing 2.
0 is thicker than the main machine casing 1 with the substantially vertical sheet path as the border (in an open state to facilitate processing operations. The above cartridge must have at least the drum 3 and at least one means for acting on the drum. 2 and 3 show the mechanism for releasing the transfer device 2 from the main machine housing 1 at this time.

In FIG. 2, when the opening/closing lever 21 is pushed in the C direction, the opening/closing lever 21 rotates in the D direction using the lever shaft 10d of the front cover 10 as the rotation axis, and the hook part 21a is moved from the 1c part of the main machine housing 1. It is detached and the lock to the main body machine casing 1 is released. At the same time, part 21b of the opening/closing lever 21 pushes down the shaft of the transfer roller 2a of the transfer device 2, and presses the pressure plate 2c.
rotates in the E direction about 1'Oa as the rotation axis until the top surface of the groove provided in the pressure plate hits the stopper 10b. In this way, in conjunction with the release operation of the locking means that locks the main body machine casing 1 and the front casing 20, the distance between the center of the tram 3 and the center of the transfer roller 2a becomes larger than the distance during image formation. The surface of the drum 3 and the surface of the transfer roller are separated.

As shown in FIG. 3, the front casing 20 is open and rotatable in the X direction relative to the main machine casing 1 around the horizontal axis 90.
When the load force on the opening/closing lever 21 is removed, it moves in the F direction around the lever shaft 10cl and stops at a predetermined position. Further, the pressure plate 2c also moves in the G direction about the rotation axis Oa until the lower surface of the groove provided in the pressure plate abuts against the stopper Qb. At this time, the transfer roller 2a and the bearing 2b are in a free state relative to the pressure plate 2c.

In this way, the front casing 20 can be opened wider than the main machine casing 1 with the substantially vertical sheet path as a boundary, and word processing work can be performed.

With respect to the movement of the transfer device 2 shown in FIGS. 1 to 3, the holder 2e having the pre-transfer kite 2f only moves in the H direction as shown in FIG. 4 with respect to the positioning kite loe of the front cover 10. , transfer roller 2a and pre-transfer kite 2f
The holder 20 including the transfer roller 2a always maintains a constant positional relationship to ensure positional accuracy between the transfer roller 2a and the pre-transfer guide 2f.

In the above embodiments, the drum and transfer roller were provided so as to be in contact with each other during image formation, but the tram and transfer roller are not limited to this and may be provided with a distance smaller than the thickness of the sheet that is the transfer material. Also good.

According to this embodiment, the positioning member 1c for the drum of the transfer device has a positioning member 1c for the drum of the process cartridge.
In addition, when the process cartridge attachment/detachment special device is opened, the transfer device is detached from the drum by the lever for opening the device, and the transfer voltage and current are reduced due to parallelism and misalignment between the drum of the process cartridge and the transfer device. increase,
It has become possible to eliminate deterioration of transfer and separation performance such as poor separation and bending of sheet materials, and to satisfy transfer performance without adjusting the position of the transfer device or improving the accuracy of parts. Furthermore, even when the apparatus is opened for jam removal or the like, it is now possible to separate the drum and transfer device at the same time as the apparatus is opened.

As described above, the drum positioning member is provided with a portion for positioning the transfer device with respect to the drum, and the transfer device is separated from the drum by the lever for opening the device when the device is opened, thereby producing the following effects.

(1) Eliminate parallelism and positional scratches between the drum and transfer device (2) Eliminate increases in transfer voltage and current (3) Eliminate separation defects (4) Eliminate bending of notebook material (5) Eliminate transfer device Eliminate the need to adjust the position relative to the drum and improve the accuracy of parts (6) / Eliminate the inconvenience of yam processing

[Brief explanation of drawings]

Figures 1 to 4 show embodiments of the present invention, Figures 1 to 3 are cross-sectional views illustrating the release mechanism of the transfer device when the device is opened, and Figure 4 is an overall cross-sectional view of the device. It is. 5 and 6 are cross-sectional views of the conventional device. 50 is the printer main body, 1 is the main body machine casing, 2 is the transfer device, 3
is a drum, 10 is a front cover, 20 is a front opening/closing lever, 21 is an opening/closing lever, and 90 is a hinge horizontal shaft.

Claims (4)

[Claims] (1) It can be divided into a first housing and a second housing that can be opened with respect to the first housing, and is provided with an image carrier and a predetermined distance from the image carrier for image formation. In the image forming apparatus, the image forming apparatus has an action means that acts on the body, a locking means that locks the first housing and the second housing, and a release means that releases the locking by the locking means, An image forming apparatus characterized in that the image carrier and the acting means are separated from each other by more than the predetermined distance in conjunction with the release operation. (2) The image forming apparatus according to claim 1, wherein the image carrier is provided in the first casing, and the operating means is provided in the second casing. (3) The image forming apparatus according to claim 1 or 2, wherein the action means is a transfer means for transferring the image on the image carrier to a transfer material. (4) Claim (3) wherein the transfer means contacts a side of the transfer material opposite to the image carrier during the transfer.
).