JPH04310972A - Transfer material carrying device - Google Patents

Abstract

PURPOSE:To prevent the dog-ear of a transfer paper caused when the curled transfer material passes a fixing part. CONSTITUTION:This device is provided with a curl detecting means 23 which detects the curl PC of the transfer material P and an air quantity adjusting means 27 which makes suction air quantity for the transfer paper P on a suction deck 3 large when the curl PC is detected by the means 23 and makes it weak when the leading edge of the transfer material P is carried to the vicinity of the fixing part. An impact at the time of entering the fixing part Y is absorbed in looseness Pa which is passing near the top part of the deck 3. Since the transfer material P enters the fixing part Y in an almost no curled state, the dog-ear of the transfer paper P is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer material conveying device for conveying a transfer material onto which a toner image has been transferred to a fixing section in an image forming apparatus such as a copying machine or a printer.

0002

2. Description of the Related Art In an image forming apparatus using powder toner, the toner transferred to a transfer material in a transfer section is heated and fused and fixed in a fixing section. However, in small image forming apparatuses, the distance from the transfer section to the fixing section may be shorter than the length of the transfer material, and in such image forming apparatuses, the transfer material may be transferred before it completely passes through the transfer section. The leading edge of the material enters the fixing section, and the impact when entering the fixing section is transmitted to the portion of the transfer material passing through the transfer section, causing so-called transfer misalignment, resulting in poor image quality.

[0003] Therefore, two air suction type conveyor devices are installed in series between the transfer section and the fixing section in the transfer material conveyance direction, and transfer between the first conveyor device and the second conveyor device is carried out. Japanese Utility Model Application Publication No. 138554/1984 proposes an image forming apparatus in which a slack (bulge) is formed in the material portion, and this slack absorbs the impact when the fixing section enters.

0004

However, the above-mentioned image forming apparatus requires two conveyor apparatuses, resulting in an increase in cost and poor space efficiency.

[0005] Therefore, the inventor of the present invention has conducted extensive research and has proposed a conveying device using a chevron-shaped suction deck. In this mountain-shaped suction deck, slack is naturally formed when the transfer material passes the top of the suction deck. That is, the transfer material lifts up from the top surface of the suction deck due to its own stiffness when passing over the top of the suction deck. Therefore, the impact when the transfer material enters the fixing section is absorbed by the slack portion and is not transmitted to the portion of the transfer material passing through the transfer section, so that transfer misalignment can be prevented.

By the way, transfer materials, especially paper, have a strong tendency to curl in low-humidity environments, and when such curled transfer materials enter the fixing section, the corners of the curled transfer materials are bent, resulting in edge creases. . In addition, in order to eliminate edge folding, the transfer material passing over the chevron-shaped suction deck can be strongly sucked and conveyed to the fixing section without curling. This means that the necessary slack cannot be formed due to the close contact with the material. However, if the suction force of the transfer material is weakened, curls cannot be eliminated.

[0007]

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and includes a transfer material conveying device that conveys the transfer material on which the toner image has been transferred in the transfer section to the fixing section. A chevron-shaped suction deck is formed in a V-shape from the top to the fixing section, and has suction ports at the bottom of the uphill and downhill slopes, and the fixing section runs along the upper surface of the suction deck from the transfer section side. a conveyor belt that moves toward the side;
a suction device that sucks the air above the suction deck through a suction port of the suction deck and uses its suction force to hold the transfer material on the conveyor belt; The first state is set until the transfer material is conveyed to the vicinity, and when the leading edge of the transfer material reaches the vicinity of the fixing unit, the second state is set to the second state, which is equal to or less than the first state.
an air volume adjustment means for setting a state, a curl detection means for detecting the amount of curl of the transfer material, and an air volume adjustment means for increasing the suction air volume in the first state according to the amount of curl detected by the curl detection means; It has been established.

[0008]

[Operation] In the transfer material conveying device, when the transfer material that has passed through the transfer section is moved onto the mountain-shaped suction deck, the transfer material is first attracted to and held by the conveyor belt at the portion facing the suction port on the upward slope, and then the conveyor belt moves along the top surface of the suction deck. Next, when the transfer material crosses the top of the suction deck, it is again attracted to and held by the conveyor belt at the portion facing the suction port on the downward slope, and is conveyed toward the fixing section. Furthermore, when the transfer material passes over the top of the suction deck, it is lifted off the suction deck due to its own stiffness, forming slack. Therefore, the impact when the leading edge of the transfer material enters the fixing section is absorbed by the slack, and is not transmitted to the portion of the transfer material passing through the transfer section, thereby preventing transfer misalignment.

On the other hand, the amount of curl on the transfer material is detected by the curl detection device, and if there is curl on the transfer material, the suction air volume is set to be increased according to the amount of curl, and the amount of curl is maintained until just before the fixing section. transported. Then, when the leading edge of the transfer material reaches the vicinity of the fixing section, the suction air volume is weakened. As a result, curls are reproduced at the leading edge of the transfer material, but since the amount of curl that recovers before entering the fixing section is small, edge folds do not occur in the transfer material passing through the fixing section. Furthermore, the transfer material that has been in close contact with the belt is lifted up due to its own stiffness, and the slack formed near the top of the suction deck is increased, thereby preventing transfer misalignment at the transfer section.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the transfer material conveying device 1 shown in FIGS. 1 and 2, the upper guide surface 3 of the suction deck 2 is formed in an "H" shape, and has an upward slope on the transfer section side (left side in the figure) with the top section 4 as the border. 5 and fixing unit side (right side in the figure)
A suction port 7 and a suction port 8 are formed at the bottom of the downward slope 6, respectively.

The conveyor device 10 includes rollers 11 and 12 provided on the fixing section side and the transfer section side of the suction deck 2, respectively.
and a plurality of conveyor belts 13 wound around these rollers 11 and 12 and disposed along the upper guide surface 3 of the suction deck 2. When the roller 11 rotates based on the drive of the motor 14, The conveyor belt 13 is configured to move clockwise in the figure. Note that the conveyor belt 13 has countless holes 13a formed therein.

The suction device 15 is disposed under the suction deck 2, and the fan 1 is operated based on the drive of the motor 17.
6 rotates, and the air on the belt is sucked through the suction ports 7, 8 of the suction deck 2 and the holes 13a of the belt 13.

The guide plate 18 is connected to the roller 11 and the fixing device 30.
A slit 19 is formed in the transfer material conveying direction.

The transfer material leading edge detection device 20 includes an actuator 21 and a switch 22.
is rotatably arranged under the guide plate 18, one end of which protrudes from the guide plate 18 through the slit 19 of the guide plate 18, and the switch 22 is operated when the actuator 21 detects the leading edge of the transfer material. It is supposed to be done.

The curl detection device 23, as shown in FIG. Above the slope 5, the light emitting elements 24a to 26a and the light receiving elements 24b to 26b are arranged vertically. In addition, the light emitting elements and light receiving elements of each stage are 24a and 24b, 25a and 25b, 26a and 26b.
are facing each other at the same level, and the light emitting elements 24a
The laser light emitted from ~26a is transmitted to the light receiving elements 24b~2.
6b, respectively.

The control device 27 controls the motors 14 and 17.
Outputs a remote signal to the switch 22, the light receiving element 24
Signals from b to 26b are input.

In the transfer material conveyance device 1 having the above configuration, when the motors 14 and 17 are driven by a signal from the control device 27, the rollers 11 and 12 and the conveyance belt 13 rotate clockwise, and the fan 16 rotates. The air above the belt is sucked through the suction ports 7, 8 and the belt hole 13a. The amount of air sucked through the suction ports 7 and 8 at this time is referred to as "initial air amount."

The transfer material P, on which the toner image has been transferred from the photoreceptor 40 at the transfer section X, is conveyed from the left side in FIG. When this transfer material P reaches the suction deck 2, the suction port 7
It is attracted and held by the belt 13 at the opposing portion. belt 1
The transfer material P held by the belt 13 is conveyed to the fixing side as the belt 13 moves, crosses the top 4 of the suction deck 2, and when it reaches the suction port 8 of the downward slope 6, the transfer material P is transferred to the fixing side by the belt 13 again.
adsorbs to. Here, since no suction port is formed near the top part 4 of the suction deck, and no suction force is applied to the transfer material P, the transfer material P is attached to the belt based on its own strength. 13, and a slack Pa is formed in the transfer material P.

The curl detection device 23 detects the amount of curl if a curl PC occurs on the transfer material P as shown in FIG. Specifically, in the curl detection device 23, the laser beams emitted from the light emitting elements 24a to 26a are received by the light receiving elements 24b to 26b. When the PC blocks the laser beam, its state (off state) is detected by the control device 27.

As shown in the flowchart of FIG. 4, the control device 27 determines whether the light receiving elements 24b to 26b are in the off state (S1, S2, S3). Then, if there is no curl PC on the transfer material P, which of the light receiving elements 24b to 26b
is also on, set the air volume up level to 0 (S4
), the suction air volume from suction ports 7 and 8 is the initial air volume (air volume V)
Keep it as it is.

If only the lower light receiving element 24b is off, the air volume increase level is set to 1 (S5), and the motor 17 is turned off.
Increase the rotation speed and increase the initial air volume by △V1 (S1
0). Similarly, when the middle and upper light receiving elements 25b and 26b turn off, the air volume up levels are set to 2 and 3, respectively (S6, 7), and the initial air volume is set to △V2 (
>△V1), increase by △V3 (>△V2) (S10
). In this manner, the larger the amount of curl, the more strongly the transfer material P is attracted, so that the transfer material P passing through the opposing portions of the suction ports 7 and 8 has almost no curl. Note that the amount of slack in the transfer material P varies depending on the amount of suction air, and the larger the amount of suction air is, the smaller the slack is, and the smaller the amount of suction air is, the larger the slack is.

The leading edge of the transfer material P, which has passed through the portion facing the suction port 8, moves on the guide plate 18 toward the fixing section, and operates the actuator 21. In the tip detection device 20, a switch 22 detects the operation of the actuator 21, and outputs the detection signal (on signal) to the control device 27 (S
8).

When the detection signal from the switch 22 is input, the control device 27 adjusts the rotation of the motor 17 and the fan 16 to set the suction air volume from the suction ports 7 and 8 to the initial air volume V (S9). As a result, the suction air volume, which had been set strongly depending on the amount of curl, becomes weaker, and the attraction force of the transfer material P to the belt 13 decreases. Further, the portion of the transfer material moving near the top portion 4 of the suction deck is further lifted up, and a sufficient slack Pa is formed in the transfer material P.

The transfer material P is further conveyed and enters the fixing section Y of the fixing device 30, where the toner image held on the upper surface of the transfer material P is heated and fixed. At this time, the impact when the leading edge of the transfer material P enters the fixing section Y propagates through the transfer material P backward (in the direction of the transfer section) and is absorbed by the slack Pa near the top portion 4. Therefore, the impact is not transmitted to the portion of the transfer material passing through the transfer section X. Therefore, the toner image transferred from the photoreceptor 40 to the transfer material P at the transfer portion X is not disturbed.

[0025] Furthermore, when the suction air volume of the suction device 15, which had been set strongly after detecting curl, is changed to the initial air volume,
The curl of the transfer material P gradually returns to its original curled state. However, in a state where the curl has slightly recovered, that is, in a state where the transfer material P does not bend even when it is clamped and pressed by the fixing section Y,
Since the leading edge of the transfer material P enters the fixing section Y, the edge of the transfer material P passing through the fixing section Y will not be folded.

In the above embodiment, when the transfer material has no curl, the suction air volume after the tip of the transfer material P is detected by the switch 22 is set to be the same as the previous suction air volume (initial air volume). , the suction air volume after the tip is detected may be smaller than the initial air volume.

Further, in the above embodiment, the amount of curl of the transfer material P is determined by three sets of light emitting elements 24a to 26a and light receiving elements 24b to
26b was assumed to be detected in combination with
The number of elements and the detection method are not limited to these.

Furthermore, in the above embodiment, the tip detection device 2
0 is provided at the position of the guide plate 18, but its installation location and configuration are not limited to this. For example, it may be determined from the registration adjustment signal and the transfer material conveyance speed that the leading edge of the transfer material is immediately in front of the fixing section, and the suction air volume may be adjusted based on this recognition.

[0029]

[Effects of the Invention] As is clear from the above explanation, according to the transfer material conveying device according to the present invention, when the transfer material has curls, the transfer material is transported in accordance with the amount of curl until the transfer material is conveyed near the fixing section. It is strongly attracted to the belt and held in a curl-free state. Furthermore, the suction force is weakened when the transfer material is conveyed near the fixing section. Therefore, when the transfer material enters the fixing section, the amount of curl is small, and the transfer material passing through the fixing section does not have edges bent, and the portion of the transfer material passing near the top of the suction deck due to a decrease in suction force. Since the slack becomes large, the impact upon entering the fixing section is absorbed by the slack and is not transmitted to the portion of the transfer material passing through the transfer section. Therefore, even if a curl-prone transfer material, such as recycled paper, is used, the transfer material passing through the fixing section will not have edges folded or misaligned in transfer.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a transfer material conveying device.

FIG. 2 is a perspective view of a transfer material conveying device.

FIG. 3 is a perspective view of a curled transfer material.

FIG. 4 is a flowchart of air volume adjustment control of the control device.

[Explanation of symbols]

1...Transfer material conveyance device 2...Suction deck 7, 8...Suction port 10...Conveyor device 13...Belt 15...Suction device 16...Fan 20...Tip detection device 23...Curl detection device 27...Control device X...Transfer section Y...Fusing part P...Transfer material Pa... slackness CPU...control device

Claims (1)

[Claims] 1. A transfer material conveying device that conveys the transfer material on which the toner image has been transferred in the transfer section to the fixing section, (a) is formed in a V-shape from the transfer section toward the fixing section, and has a structure that extends upward from the transfer section toward the fixing section. (b) a conveyor belt that moves along the upper surface of the suction deck from the transfer section side toward the fixing section side; (c) the above-mentioned (d) a suction device that sucks the air above the suction deck through a suction port of the suction deck and uses the suction force to hold the transfer material on the conveying belt; an air volume adjusting means that sets the transfer material to a first state until it is conveyed near the fixing section, and sets it to a second state that is equal to or less than the first state when the leading edge of the transfer material reaches the vicinity of the fixing section; e) a curl detection means for detecting the amount of curl of the transfer material; and (f) an air volume adjustment means for increasing the suction air volume in the first state according to the amount of curl detected by the curl detection means. A transfer material conveying device characterized by: