JPH02287374A - Printer - Google Patents

Abstract

PURPOSE:To arrange the directions of ejecting paper at the time of one-surface printing and at the time of both-surface printing by providing a switchback(S/B) mechanism which switches back the paper where both-surface printing is completed to eject to a stack part after temporarily sucking the paper in a branching conveyance path. CONSTITUTION:The S/B mechanism 31 is provided in the branching conveyance path 32 of a paper inversion mechanism 30 for both-surface printing. In the case of one- surface printing, the paper inversion mechanism 30 and the S/B mechanism 31 are not actuated and paper which passes a printing part is ejected to the stack part. In the case of both-surface printing, the paper inversion mechanism 30 and the S/B mechanism 31 are actuated. The paper where one-surface printing on the back surface is completed advances in the branching conveyance path 32 by operating a selector valve 33. It is inverted by the inversion mechanism 30 and returned to the conveyance path 32, then printing is performed to the surface of the paper. Then, the paper where both-surface printing is completed is sucked in the branching conveyance path 32 again, where the switchback by the S/B mechanism 31 is executed, and the paper is ejected to the stacker part. Thus, the directions of ejecting paper at the time of one-surface printing and at the time of both-surface printing are arranged.

Description

[Detailed description of the invention] 〔overview〕 Regarding printing devices that print on one side and both sides of paper, Single-sided without increasing the cost or size of the device.

With the aim of aligning the directionality of ejected paper during duplex printing, the machine is equipped with a paper reversing mechanism for duplex printing that includes a branch conveyance path that branches off from the conveyance path that ejects the paper that has passed through the printing section to the stack section. In the printing apparatus, the branch conveyance path is provided with a switch bank mechanism for once sucking the paper on which double-sided printing has been completed into the branch conveyance path, and then switch-banking the sheet and discharging it to the stack section.

[Industrial application field]

The present invention relates to a printing device that prints on one side and both sides of paper.

In recent years, with the spread of data processing technology using computers, the amount of paper used to output computer output data information on printers has increased. has been sought after.

In response to this demand, printers that can print on both sides of cut paper and perform high-speed processing are fully capable of fulfilling their role and meeting user demands, and manufacturers are increasing the number of printers that have these specifications. It is being provided. The present invention relates to a printing device that can provide both double-sided printing and single-sided printing modes, and in particular to a mechanism for controlling the stacking direction of pre-punched paper. , which can be simplified.

[Conventional technology]

This type of conventional printing device can be roughly divided into three types (see below).
1) to (3)), and the effects of these configurations 1 are as follows.

(1) Switchback (hereinafter abbreviated as S/B)
Mechanism-less type: The structural outline of this type of printing device is shown in Figures 4 and 5. In the figures, 1 is a photosensitive drum, 2 is a suction belt for conveying paper, 3 is a fixing device, and 4 is an ejector. roller, 5 is a paper reversing mechanism for double-sided printing, 6 is a selector valve, L, 7g, 7
i is a feed roller. Although not shown, a known image forming means consisting of a pre-charging device, an exposure optical system, and a developing device is provided around the photosensitive drum 1. Furthermore, after the image is transferred to paper by a transfer device (not shown), the photosensitive drum 1 is A static eliminator and a cleaner are provided to remove residual toner on the image forming apparatus 1.

During recording, the photosensitive drum 1 is rotated in the counterclockwise direction indicated by the arrow, and a toner image is formed on its surface by an image forming means. On the other hand, the paper is transported from the paper feed section to the horizontal transport path 8 at a predetermined timing with the operation of the image forming means. The photosensitive drum 1 is fed out by a feed roller 72.7□ to a transfer position (a position where a transfer device (not shown) faces the photosensitive drum 1 at the top).

Then, here, the toner image is transferred onto the paper by the transfer device. Thereafter, the paper is conveyed by the suction belt 2 and sent to the fixing device 3, where the toner image is fixed 6.
In the case of single-sided printing, the selector valve 6 is positioned as shown by the chain line, and the paper on which the toner image has been fixed is transferred to the feed roller 7.
3 to the left, and is discharged to the stacker section by discharge rollers 4. Pre-punched paper 1 for this one-sided printing
The paper flow of 00 is shown in FIG. 6 Fa+.

The numbers ■ to ■ in the figure are numbers given to indicate the order of paper flow. In this case, printing (letter A in the figure) is performed on the back side, and the paper is discharged to the stacker with the punch hole 100a on the right side.

Further, in the case of double-sided printing, the selector valve 6 is positioned as shown by the solid line. In this case, the paper that has been printed on the back side as described above is transferred to the paper reversing machine flI by the selector valve 6.
Guided into s, branch conveyance path 8! and is sent to the reversing section 9. Here, the paper 100 is once sucked into the suction space 13 by a first roller (raking roller) 10 and a third roller (pinch roller) 12, and then
0 and the second roller (pinch roller) 11 to the right, and is transported to the horizontal conveyance path 8. will be returned to. 15 is a reversing roller, and 16 is a reversing pinch roller. During this time, a toner image for surface printing is formed on the photosensitive drum 1, and the toner image returns to the horizontal conveyance path 81 and is sent to the transfer position by the feed roller rough □. ). Thereafter, the transferred toner image is fixed by the fixing device 3 and enters the feed roller 73 in the same manner as described above. At this point, the selector valve 6 has been returned to the state shown by the chain line, and the feed roller 7. The paper 100 that is fed is ejected to the stacker section by the ejection roller 4. The paper flow of the pre-punched paper lOO in the case of this double-sided printing is as shown in FIG. ■ to ■ in the figure are numbers indicating the order of paper flow, and A
is a character printed on the back side, and T is a character printed on the front side.

(2) Separate S/B mechanism type: This is the S/B mechanism shown in Figure 7, which is specially designed for double-sided paper printing.
The paper is S/Bed by a mechanism, and in the figure, 21 is a conveyance path, 22 is a branch conveyance path for S/B, 23 is a perforated belt provided in the branch conveyance path 22, and 24 is for air suction. 25 is a feed roller, and 26 is a swingable paper guide. This S/B mechanism is used by being placed between the selector valve 6 and the discharge roller 4 shown in FIGS. 4 and 5, for example.
Its action is as follows.

During single-sided printing, the paper guide 26 is positioned as shown by the chain line, and the paper that has been fixed enters the conveyance path 21 as shown by the arrow, is sent by the feed roller 25, and is discharged to the stacker section. Further, during double-sided printing, the paper guide 26 is positioned as shown by the solid line, and the paper that has completed fixing and enters the transport path 21 and is sent by the feed roller 25 is guided by the paper guide 26 and enters the branch transport path 22. do. This paper is drawn into the branch conveyance path 22 by a perforated belt 23 that is driven by a drive system (not shown) and runs in the direction of the arrow. The perforated belt 23 starts traveling in the direction of the arrow A' when the trailing edge of the paper passes the paper guide 26, and the paper once drawn into the branch conveyance path 22 as described above is moved by the perforated belt 23 in the direction of the arrow A'. It is conveyed in the A' direction and discharged to the stacker section. In this case, the fan 24 sucks air through the holes 23a of the belt 23 to suck and hold the paper onto the belt 23, and the rear end 26a of the paper guide 26 guides the ejected paper. and,
By performing S/B using this S/B mechanism, the orientation of the paper discharged during double-sided printing is the same as the orientation of the paper discharged during single-sided printing (the punch holes are on the same side). Figure 8 (a) shows the paper flow during single-sided printing, and Figure 8 (
b), (C) shows the paper flow during double-sided printing,
O indicates the order of paper flow. It is clear from this figure that the orientation of the paper is the same during single-sided printing and two-sided printing.

(3) S/B mechanism transport bus (inside stacker) installation type; This separates the paper flow in the stacker during single-sided/double-sided printing and aligns the paper orientation. Figure 9 shows the paper flow in the stacker. It shows the flow. Fig. 9 f8) shows the case of double-sided printing, in which the paper 100 is printed (letter A) on the back side during O1■, then reversed as 0.0.0, and printed on the front side during ■■. It is printed (T character) and ■
, ■, and ■, and are stacked on the stacker 101□ or the stacker 1011 as in ■ or ■.

In addition, FIG. 9 (bl shows the case of single-sided printing, paper 10
0 is printed on the back side (A character) between O1■, ■,■
, ■, ■, ■, ■ are stacked on each stacker. In both of these cases of FIGS. 9(a) and (b),
The sheets are stacked with the punch holes 100a on the right side.

[Problem to be solved by the invention]

However, each of these conventional devices has the following drawbacks.

(Type without 11S/B mechanism; the punch hole positions of stacked sheets are reversed when printing on one side and on both sides, so appropriate measures must be taken during subsequent processing (stapling with a stapler, sorting with a sorter, etc.) In addition, in the case of this method, attempts have been made to perform single-sided printing in double-sided printing mode, leaving the back side of one side blank and aligning the punch holes, but this requires caution in how the customer uses it. Moreover, it is disadvantageous because software changes are required when replacing with other companies' machines, and post-processing (replacement) is difficult if used incorrectly.

(2) Separate S/B mechanism type: This is a type in which paper is S/Bed by a specially provided S/B mechanism, which is disadvantageous in terms of cost and device space.

(3) S/B mechanism transport bus (inside stunker) installation type; Because the system largely separates double-sided/single-sided paper flow within the stacker, the device becomes larger (especially in terms of height).

The present invention enables single-sided 2-sided printing without increasing the cost or increasing the size of the device.
It is an object of the present invention to provide a printing device that can align the directionality of ejected paper during double-sided printing.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a printing apparatus equipped with a paper reversing mechanism for double-sided printing that includes a branch conveyance path that branches from a conveyance path that discharges the paper that has passed through the printing section to the stack section. A switchback mechanism is provided in the path for once sucking the paper that has undergone double-sided printing into the branch conveyance path, and then switching back and discharging it to the stack section.

[For production]

During single-sided printing, the paper reversing mechanism and switchback mechanism do not operate, and the paper that has passed through the printing section is discharged to the stack section.

During double-sided printing, a paper reversing mechanism and a switchback mechanism operate. The paper flow in this case is as follows.

The paper that has undergone single-sided printing on the back side enters the branch conveyance path by operating a selector valve or the like, is reversed by a paper reversing mechanism, and returned to the conveyance path. Then, printing is performed on the surface of this paper. The paper on which double-sided printing has been completed in this manner is sucked into the branch conveyance path again, where switchback is performed by the switchback mechanism. Thereafter, the paper is discharged to the stacker section.

In this way, in the present invention, since the paper with double-sided printing is switched back in the branch conveyance path and then discharged to the stack section, the directionality of the discharged paper is determined by changing the direction of the paper printed on both sides of the paper after being printed on one side. The orientation of the paper can be aligned. Moreover, since the switchback mechanism is provided by utilizing the branch conveyance path of the conventional device, the device does not become larger and is advantageous in terms of cost.

〔Example〕

The present invention will now be described in detail with reference to FIGS. 1-3.

The above-mentioned FIG. 5 is a side view showing the main part structure of the paper reversing mechanism of the printing apparatus shown in FIG. This makes it possible to align the directionality of ejected paper during single-sided and double-sided printing.

Next, the configuration of the S/B mechanism will be explained with reference to FIG.

The S/B mechanism 31 includes a branch conveyance path 32 and a selector valve 33.
, an auxiliary pinch roller 34, and a first . Second guide plate 3
5.36, a sensor 37, and rollers 10 and 12 (also used as the paper reversing mechanism 30). The paper reversing mechanism 30 is
It is similar to the conventional paper reversing mechanism 5 except for the branch conveyance path 32. The branch conveyance path 32 differs from the branch conveyance path 8□ in that a relief 38 for sucking and discharging paper is provided at the lower left side. The selector valve 33 is provided at the same position as the selector valve 6 in FIG. 5, but the selector valve 6 is different from the selector valve 6 because the paper once sucked into the branch conveyance path 32 is S/Bed and discharged to the stacker section. The shape and swing angle are different. This selector valve 33 is driven by a rotary solenoid (not shown) to determine its swing angle. Auxiliary pinch roller 34. 1st
guide plate 35. Second guide plate 36. and sensor 37
are provided along the branch conveyance path 32 as shown in the figure, and the first . The second guide plate 35.36 is adapted to be driven by a rotary lenoid 39.40.

The operation of the S/B mechanism having such a configuration is as follows.

In the case of single-sided printing, the selector valve 33 is positioned as shown in FIG. 2(a), and the paper that has passed through the transfer section and the fixing device (printing section) is discharged to the stacker section.

On the other hand, in the case of double-sided printing, after completing single-sided printing, the
), the selector valve 33 is positioned at the duplex printing paper processing position, and the first guide plate 35 is moved by the rotary solenoid 39 to descend in the direction of the arrow. Therefore, the paper on which one-sided printing has been completed is transferred to the selector valve 33.
Then, it enters the branch conveyance path 32 while being guided by the first guide plate 35 . After that, the paper is reversed and printing is performed on the front side according to the paper flow shown in FIG.
Reach 3. Thereafter, when the paper is sucked into the branch conveyance path 32 and the sensor 37 detects the paper again, the first guide plate 35 rises to its original position. Then, the leading edge of the paper is sent by the auxiliary pinch roller 34 toward the scraping roller 10. When the sensor 37 detects the trailing edge of the paper, the roller 10 temporarily stops and then begins to rotate in reverse, transporting the paper back toward the selector valve 33. Along with this, the selector valve 33
is positioned in the state shown in Fig. 2 (C) and guides the paper to the stacker section, but at this time, the second
The guide plate 36 is driven by the rotary solenoid 40 and comes down to prevent the paper from flowing toward the fixing device. As a result, the direction of the paper is reversed and the paper is discharged to the stacker section. In this case, the orientation of the paper is the same as when printing on one side due to the adoption of the S/B mechanism.

FIG. 3 shows the paper flow during double-sided printing.

Note that when the trailing edge of the paper discharged to the stack unit after double-sided printing and S/B passes through the sensor 41 shown in FIG. 2(C) as described above, the second guide plate 36 returns to its original position. Return to state.

〔Effect of the invention〕

As described above, according to the present invention, by installing the S/B mechanism using the branch conveyance path that has conventionally been provided for double-sided printing, the cost and size of the apparatus do not increase. It is possible to align the directionality of ejected sheets during single-sided, two-sided printing, and there is no need to align the directions of the sheets after stacking. In addition, there are no restrictions on the use of pre-punched paper, increasing market competitiveness.

[Brief explanation of drawings]

FIG. 1 is a side view showing the main structure of a printing device according to an embodiment of the present invention; FIGS. The same figure shows the paper flow during double-sided printing. Figure 4 is a schematic diagram of the structure of a conventional printing device without S/B mechanism. Figure 5 is a side view showing the main structure of Figure 4. Diagram (a)
, fbl is an explanatory diagram of the paper flow during printing by the device in FIG. 4, FIG. 7 is an explanatory diagram of the structure of the separate type S/B mechanism of the conventional printing device, and ) is an explanatory diagram of the paper flow in the S/B mechanism in Figure 7, and Figures 9(a) and (b) are diagrams of the paper flow in the stacker of another conventional printing device. In the figure, 81 is a conveyance path. , 30 is a paper reversing mechanism, 31 is a switchback mechanism, and 32 is a branch conveyance path.

Claims (1)

[Claims] A conveyance path (
In a printing device equipped with a paper reversing mechanism for double-sided printing including a branch conveyance path (32) branching from the branch conveyance path (32), the paper on which double-sided printing has been completed is once transferred to the branch conveyance path (32). A printing apparatus characterized in that a switchback mechanism (31) is provided for inhaling and then switching back and discharging to the stack section.