JPH0293666A - Image output device - Google Patents

Abstract

PURPOSE:To adjust a distance between a photosensitive drum and a paper conveying and transferring drum and to always keep it constant by providing a rocking and supporting mechanism and controlling the rocking state of a rocking frame unit incorporating the photosensitive drum. CONSTITUTION:A cleaning device, an electrostatic charger, a developing unit, the photosensitive drum and motors for driving them are disposed in the rocking frame unit 24. A sliding frame 20 is mounted in a main frame 22 so that it can be pulled out in he axial direction of the transferring and conveying drum 3 and, moreover, the rocking frame 24 is pivotally mounted in the rocking frame 20 so that it can freely rock. Therefore, the distance between the photosensitive drum 12 mounted in the rocking frame 24 and the transferring and conveying drums 3 can be adjusted. Thus, the distance between the photosensitive drum 12 and the transferring and conveying drum 3 can be made optimum by rocking the rocking frame 24 by the use of cam mechanism 26 and 27 and a tracking roll, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image output device such as an electronic copying machine, and in particular,
The present invention relates to an image output device using a photosensitive drum and a transfer conveyance drum that is pressed against the photosensitive drum.

[Conventional technology]

For example, in a color electronic copying machine, it is necessary to multiple-transfer images made of a plurality of color materials, such as color toners, onto a sheet of paper.

As a means for realizing this multiple transfer, there is a method in which a plurality of image forming units corresponding to each color are arranged around a transfer conveyance drum. Each image forming unit has a photosensitive drum and a developing device.

A cleaner and the like are arranged, and toner images of respective colors are formed on the photosensitive drums in each image forming unit. Each photosensitive drum is brought into pressure contact with a common transfer conveyance drum, so that the toner images on each photosensitive drum are multiple-transferred onto the transfer conveyance drum. As a result, a color image is obtained on the transfer and conveyance drum, which is transferred to paper and then fixed to obtain a color copy.

[Problem to be solved by the invention]

In this way, in an image output device that performs multiple transfer by pressing each photosensitive drum against the transfer/conveyance drum, it is necessary to always maintain a constant distance between the photosensitive drum and the transfer/conveyance drum.

However, due to manufacturing precision or changes over time,
It is difficult to keep the above distance constant with high precision. For this reason, there have been problems in that the image is not sufficiently transferred from the photosensitive drum to the transfer/conveyance drum, or the transfer position from each photosensitive drum to the transfer/conveyance drum is shifted, resulting in color misregistration.

Furthermore, when repairing or maintaining functional parts such as the photosensitive drum, developer, and cleaner installed in each image forming unit, the entire image forming unit must be removed from the main body of the image output device, resulting in poor work efficiency. There was also the problem.

The present invention was devised to solve the above-mentioned problems, and aims to improve workability during repair and maintenance while always keeping the distance between the photosensitive drum and the transfer conveyance drum constant. purpose.

[Means to solve the problem]

In order to achieve the above object, the image output device of the present invention includes a sliding frame that is attached to a main frame on which a transfer and conveyance drum is pivotally supported so that it can be pulled out in the axial direction of the transfer and conveyance drum, and a sliding frame that is A swinging frame is pivotably mounted on the swinging frame, an image forming means including a photosensitive drum is attached to the swinging frame, and the distance between the transfer conveyance drum and the photosensitive drum is maintained substantially constant. The present invention is characterized in that a swing support mechanism for swinging the swing frame is provided.

As the swing support mechanism, a cam provided on the main frame and a cam follower provided on the swing frame and engaged with the cam can be used.

Further, as the swing support mechanism, a tracking roll that is provided coaxially with the photosensitive drum and presses against the circumferential surface of the transfer conveyance drum can also be used.

[Function] In the present invention, the sliding frame is attached to the main frame so that it can be pulled out in the axial direction of the transfer conveyance drum,
Further, a swinging frame is pivotally attached to the sliding frame so as to be swingable. Therefore, the distance between the photosensitive drum attached to the swing frame and the transfer conveyance drum can be adjusted. Accordingly, by swinging the swinging frame using a cam groove, a tracking roll, etc., it is possible to optimize the distance between the photosensitive drum and the transfer conveyance drum.

〔Example〕

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, features of the present invention will be specifically described based on examples with reference to the drawings.

FIG. 1 shows an overall view of an image output device according to an embodiment of the present invention.

In the figure, 1 indicates a paper feed tray, and this paper feed tray l
The paper a accommodated in the image output device 12 is sent out by the feed roll 2 into the image output device 12 .

A paper conveyance transfer drum 3 that rotates counterclockwise in the drawing is arranged in the center of the image output device, and around this paper conveyance transfer drum 3 there are four drums for copying color images. An image forming unit 45.6.7 is provided. Further, the paper transport transfer drum 3 is provided with a gripper (not shown) that grips the leading edge of the paper a.

A sheet or mesh made of an insulating material is pasted on the paper transport transfer drum 3, and an electric charge is applied to this sheet or mesh in advance by a corotron 8.

Then, when an actuator (not shown) provided near the gripper of the paper transport transfer drum 3 reaches the reference sensor IO, the registration roller 9 starts rotating based on the output of the reference sensor 10 and feeds out the paper. At this time, the gripper is opened by being driven by a cam (not shown), but the position, shape, etc. of the cam are adjusted so that it can grip paper a in a timely manner when paper a is sent. There is.

Since the sheet or mesh is electrically charged, the paper conveyance transfer drum 3 attracts the paper a fed by the registration roller 9 and sequentially conveys it to each transfer section of each image forming unit 4.5, 6.7. do.

Then, at each transfer section of each image forming unit) 4, 5, 6.7, the toner images on the photosensitive drum 12 are multiple-transferred onto the paper a by the transfer corotron 11.

When the leading edge of paper a reaches the peeling corotron 13, the gripper is again driven by another cam (not shown) to open and release paper a, and at the same time the electrostatic adsorption force of paper a on the sheet or mesh increases. The sheet a is weakened by the peeling corotron 13 and is peeled off from the sheet transport transfer drum 3, passes through the fixing device 14, and is discharged onto the sheet discharge tray 15.

Here, the image forming operations of the four image forming units) 4, 5, 6, and 7 will be briefly described. Note that since each unit has the same configuration, a common explanation will be given below.

In the figure, 16 indicates an RO5 (raster output scanner) equipped with a rotating polygon mirror, and this RO316 scans the photosensitive drum 12 with light such as a laser. At this time, a latent image is formed on the photosensitive drum 12, which has been charged in advance by the charger 17, by turning on and off light from a laser or the like in accordance with an image signal stored in a memory or the like. This latent image is developed by the developing unit 18, and a toner image is formed on the photosensitive drum 12. Furthermore,
This toner image is transferred onto paper a by the transfer corotron 11.

Residual toner left on the photosensitive drum 12 is scraped off by a cleaning device 19 and discharged to the outside.

Next, details of the mounting structure of the image forming units (4.5, 6.7) will be explained with reference to FIG.

In the figure, reference numeral 20 denotes a sliding frame unit for supporting the image forming unit in a slidable manner with respect to the main frame 22 of the image output device. is supported and fixed to the main frame 22. The sliding frame unit 20 also includes a pair of slide rails 23 (first
(see figure), and is supported by the main frame 22 so that the entire unit can be pulled out to the outside of the main frame 22. Note that the paper conveyance transfer drum 3 is pivotally supported by the main frame 22.

Additionally, a swing frame unit 24 is attached to the sliding frame unit 20, and a pivot shaft 25 (see FIG. 1)
and is supported by a cam 26 and a cam follower 27.

The swing frame unit 24 includes the cleaning device 19. Charger 17. Developing unit 18. Photosensitive drum 12
and their drive motors are provided.

The sliding frame unit 20 is fixed to the main frame 22 with a positioning support pin 21, but the swinging frame unit 24 is fixed to the sliding frame unit 20 or the main frame 22 with a pivot axis, as described below. The cam 26 can be rotated by rotating the cam 26 around the cam 25.

A cam 26 for swinging the swinging frame unit 24 is fixed to a camshaft 29, and this camshaft 29 is rotatably supported by the sliding frame unit 20.

The cam 26 has a long groove 26 in the circumferential direction as shown in FIG.
The radius of this long groove 26a changes slightly depending on the angle, for example, it changes by about 300 μm with a rotation of about 300 degrees. In addition, the cam follower 27 is
It consists of a support plate 27a fixed near the free end of the swing frame unit 24, and a pin 27b set up at the tip of the support plate 27a, and the pin 27b engages with the long groove 26a. ing.

Therefore, when the cam 26 is rotated, the pin 27b of the cam follower 27 engaged with the long groove 26a moves slightly in the radial direction of the paper conveyance transfer drum 3, and the swing frame unit 24 uses the pivot shaft 25 as a fulcrum. swaying as
The photosensitive drum 12 has a distance of about 300 mm relative to the paper transport transfer drum 3.
Swings up and down by μm.

This swing motion is driven by a motor 28 fixed to the main frame 22. That is, as shown in FIG. 4, a displacement sensor 41 provided on the swing frame unit 24 measures the distance between the paper transport transfer drum 3 and the photosensitive drum 12 in the transfer portion, and the A/D converter 4
After converting it into a digital signal by step 2, a signal is sent to the motor controller 43 to make the distance constant.

A motor driver 44 rotates the motor 28 in response to a signal from the motor controller 43. The motor 28 rotates the cam 26 in response to a signal corresponding to the distance between the paper transport transfer drum 3 and the photosensitive drum 12. By this operation, the cam follower 27 provided in the swing frame unit 24 follows the cam 26, and the swing frame unit 24 can be caused to swing.

Through this correction operation, the distance between the photosensitive drum 12 and the paper transport transfer drum 3 could be kept constant with a variation of 60 μm or less.

In this embodiment, a 5-phase stepping motor is used as the motor 28, and the distance is adjusted with an accuracy of 0.5 μm per step, but a DC servo motor is used to continuously adjust the distance. It's okay.

Further, in this embodiment, the time for one revolution of the paper transport transfer drum 3 is divided into 36 parts, and a signal is sent to the motor 28 to correct the distance between the photosensitive drum 12 and the paper transport transfer drum 3 for each division. sending. In general, the smaller the number of divisions, the better; however, if the number of divisions is too small, the motor controller 43 for making the motor 28 follow the motor becomes complicated, leading to an increase in cost. Therefore, an appropriate number of divisions may be selected based on the balance between correction accuracy and cost.

The cam 26 also has the role of separating the photosensitive drum 12 and the paper transport transfer drum 3 when the sliding frame unit 20 is pulled out of the main frame 22.

That is, the radius of the long groove 26a formed in the cam 26 is
Since the long groove 26a suddenly becomes smaller at one end 26b, by turning this cam 26 all the way, the swing frame unit 24 is held at that position, for example, at a distance of about 3+n+n from the paper transport transfer drum 3. be able to. Therefore, the sliding frame unit 20 can be pulled out of the main frame 22 without resistance. This operation can be performed by a lever 30 attached to the camshaft 29.

In addition, in the previous embodiment, the sliding frame unit 20 is supported by the main frame 22 by the positioning support bin 21,
The swinging frame unit 24 is supported by the sliding frame unit 20 by a pivot shaft 25 and a cam follower 27. However, the configuration is not limited to this, and as shown in FIG.
0 is supported by the main frame 22 with the positioning support pin 21, and the swinging frame unit 24 is supported with respect to the main frame 22 by the pivot shaft 25 (see FIG. 1), and is also supported by the swinging frame unit 24. The swinging frame unit 24 may be supported by a tracking roll 32 provided coaxially with the light body axis 31 and in contact with the paper conveyance transfer drum 3 .

That is, when the paper transport transfer drum 3 rotates, the tracking roll 32 also rotates and swings around the pivot shaft 25 to follow the paper transport transfer drum 3. At this time, in order to prevent excessive load torque from being applied to the reverse transfer drum 3, the sliding frame unit 20 is pulled up by a counterbalance spring 33 (see FIG. 1). Note that the stopper 34 prevents the sliding frame unit 20 from falling.

As described above, in this embodiment, the swing frame unit 24 is attached to the sliding frame unit 20 that can be pulled out.
The sliding frame unit 20 and the swinging frame unit 24 are pivotally mounted, and functional devices necessary for electrophotographic copying are mounted on the swinging frame unit 24. You can pull it out and work on it, improving work efficiency. Further, since the swinging frame unit 24 is swingably supported with respect to the sliding frame unit 20, the transfer conveyance drum 3 and the photosensitive drum 1
It becomes possible to arbitrarily adjust the distance from 2.

〔Effect of the invention〕

As described above, according to the present invention, the swinging support mechanism is provided to control the swinging state of the swinging frame unit in which the photosensitive drum is built, so that the photosensitive drum and the paper transport transfer drum You can adjust the distance to keep it constant. As a result, even if, for example, there are variations or changes in the dimensions of the paper transport transfer drum, optimal transfer conditions can always be ensured and good transfer can be performed. Further, since the sliding frame housing the image forming means including the photosensitive drum that is pressed against the transfer conveyance drum is detachably attached to the main frame, maintenance work and the like are facilitated.

[Brief explanation of drawings]

FIG. 1 is an overall view of an image output device according to an embodiment of the present invention, FIG. 2 is a side view of a main part of a unit device used in the image output device, and FIG. 3 is a front view of a main part showing an example of a swing support mechanism. figure,
FIG. 4 is a block diagram of a distance correction circuit, and FIG. 5 is a side view of a main part of an image output device according to another embodiment of the present invention. 1: Paper feed tray 2: Feed roll 3: Paper transport transfer drum 4, 5.6.7: Image forming unit 8: Corotron 9 Ni registration roller XO: X quasi-sensor 11; Transfer corotron 12: Photosensitive drum
13: Peeling corotron 14: Fixing device 15:
Paper discharge tray 15: ROS 17: Charger 18: Developing unit 19: Cleaning device 20: Sliding frame unit 21: Positioning support pin 22: Main frame 23 Ni slide rail 24: Swinging frame unit 2
5: Pivot shaft 26: Cam 26a: Long groove 26b = One end 27: Cam follower 27a: Support plate 27b: Pin 28:
Motor 29: Cam shaft 30 Lever 31: Photoreceptor shaft 32 Racking roll 33
: Counter balance spring 34: Stopper

Claims (1)

[Scope of Claims] 1. A sliding frame is attached to the main frame on which the transfer and conveyance drum is pivotally supported so that it can be pulled out in the axial direction of the transfer and conveyance drum, and a sliding frame is attached to the sliding frame so as to be able to swing. A frame is pivotally mounted, an image forming means including a photosensitive drum is attached to the swinging frame, and the swinging frame is swinged so that the distance between the transfer conveyance drum and the photosensitive drum is maintained substantially constant. An image output device characterized by being provided with a swinging support mechanism that allows the image to be output. 2. The swing support mechanism includes a cam provided on the sliding frame side and a cam follower provided on the swing frame side and engaged with the cam. image output device. 3. The image output device according to claim 1, wherein the swing support mechanism includes a tracking roll that is provided coaxially with the photosensitive drum and presses against the peripheral surface of the transfer conveyance drum.