JPH0668646B2 - Image forming apparatus having a multi-conveying function - Google Patents

Description

Description: TECHNICAL FIELD The present invention includes a main conveyance path and a sub-conveyance path inside an apparatus,
The present invention relates to an image forming apparatus having a multi-conveying function that selectively allows a transfer material to pass through a process section once or continuously.

<Summary of the Invention> In summary, the image forming apparatus having the multiplex conveying function according to the present invention is provided with an image forming stop means for stopping the image forming operation of the process section, and is used for the second and subsequent transfer materials in the multiplex conveying mode. By making the image formation stopping means effective when passing through the process section, the fixing step is executed a plurality of times for the image transferred onto the transfer material so that a sufficient fixing effect is obtained.

<Prior art and its drawbacks> In an image forming apparatus using an electrophotographic method, an overhead projector film (hereinafter referred to as an OHP film) is used as a transfer material in addition to plain paper, and a developer image is formed on the OHP film. There are cases. Thus, when forming an image on an OHP film, a developer containing a polyester-based toner having excellent light projecting property is used. However, the surface state of the polyester-based toner is rough in the state where the normal copying process is completed, and when the light is emitted from the projector, the toner is diffusely reflected on the surface of the image, and the color reproducibility of the color toner becomes insufficient, resulting in an image failure. The color becomes dark.

For this reason, conventionally, the copying process was once completed and the image was transferred.
The transparencies were manually fed again and passed through the image forming apparatus without forming an image. This is because the surface of the image after the fixing process is once heated and pressed again so that the surface of the image is smoothed and irregular reflection is prevented.
However, the OHP film once discharged to the paper discharge section has to be re-fed by manual feeding, which has a drawback that the work becomes complicated and the time is extended.

Also, when an image is formed using an OHP film as a transfer material, the feeding speed of the fixing device is reduced to lengthen the contact time of the transfer material with the fixing device and improve the fixability so that the surface is formed smoothly. There was something I did. This is to improve the fixing effect without bothering the operator. However, in the above-mentioned image forming apparatus, the transfer material conveying device has to be constructed at a variable speed, and there is a drawback that the cost increases. In addition, there is a drawback that the amount of heat applied to the OHP film increases due to a longer contact time between the OHP film and the fixing device, and the OHP film having thermoplasticity as an attribute is deformed.

<Purpose of the Invention> An object of the present invention is to use an image forming apparatus having a multi-conveying function to guide an OHP film that has completed image formation to a fixing device a plurality of times so that the surface of a developer image can be smoothed. , The work of forming a smooth image on the surface of the OHP film can be easily performed, and the cost increase of the device is prevented,
Another object of the present invention is to provide an image forming apparatus having a multi-transport function capable of eliminating the deformation of the transparencies.

<Structure of the Invention> The present invention is an image forming apparatus including a main conveyance path from a paper feed section to a paper ejection section via a process section, and a sub-conveyance path connecting the paper ejection section to the process section. In the above, in the image forming apparatus, the transfer material that has passed through the process section is guided again to the process section in the same direction through the sub-conveyance path to form multiple images, and the transfer material that has passed through the process section is conveyed through the sub-conveyance path. A double-sided image forming unit that guides the image to the process unit again on the back side and forms images on both sides, a fixing number storage unit, and a transfer material that has passed through the process unit is stored in the fixing number storage unit by the number of sub-conveyance paths. A multi-fixing unit that guides the process through the process unit and stops the paper feeding operation and the image forming operation of the process unit during this period to perform only the fixing operation; Characterized by comprising a mode selection means for selecting one, from.

<Operation> With the above configuration, the image forming operation in the process unit is stopped by enabling the image forming unit.

When the multiple fixing means is selectively input by the mode selecting means, the image forming stopping means becomes effective when the transfer material passes through the process section for the second time and thereafter in the multiplex transport mode.

When the image formation stopping means is activated in the multi-transport mode, the developer image formed on the transfer material passes through the fixing device a plurality of times.

<Effect of the Invention> According to the present invention, the transfer material on which the developer image is formed can be passed through the fixing device a plurality of times by selectively inputting the multiple fixing means. As a result, the surface layer of the developer image is sufficiently subjected to the fixing effect and the surface is smoothed. Therefore, even when the OHP film on which the developer image is formed is projected onto the projector, the light of the projector does not diffusely reflect on the surface of the developer image,
The color of the developer image can be faithfully reproduced. Moreover, since the existing multi-conveying function of the image forming apparatus is used, a dedicated structure is not required, and it is possible to prevent the apparatus from becoming complicated and the cost from increasing. Further, the operator's manual work for passing the transfer material a plurality of times through the main conveyance path and the sub-conveyance path formed inside the image forming apparatus is not required, and the work can be simplified. Also, transparencies are
Since it passes through the fixing device at the same speed as normal speed, OHP
The amount of heat applied to the film does not rise excessively and deformation does not occur.

<Example> The present invention will be described below using a copying machine as an image forming apparatus.

FIG. 2 is a schematic front sectional view of a copying machine having a multiplex transport function according to an embodiment of the present invention.

A photoconductor drum 22 is provided in the center of the inside of the copying machine main body 21, and a charging charger 23, a developing device 24, a transfer / transfer device, and a transfer / transfer device 24 are provided around the photoconductor drum 22.
The peeling charger 25, the cleaner 26, and the like constitute the copying process unit 27. Paper cassettes 28 and 29 and a manual paper feed tray 30 are attached to one side surface of the copying machine main body 21 to form a paper feed unit 31. The paper feed unit 31 is equipped with paper feed rollers 32 to 34, and the paper cassettes 28, 2
Feed paper from either 9 or the manual feed tray 30. A fixing device 35 including a pair of rollers is provided inside the copying machine main body 21. The pair of rollers is heated to a temperature at which the developer can be melted by a heater lamp (not shown), and heats and pressurizes the transfer material to fix the developer image. The fixing device 35 is provided in the vicinity of the other side surface of the copying machine main body 21, and the paper sheet that has passed through the fixing device 35 is discharged to the outside from the paper discharge section 37 by the paper discharge roller 36. Conveying rollers 38 to 40 and a conveying belt 41 are provided between the paper feeding unit 31 and the paper discharging unit 37 via the copying process unit 27 to form a main conveying path 42.

A double-sided conveyance section 51 is attached to the other side surface of the copying machine main body 21. Inside the double-sided conveyance section 51, sub-conveyance rollers 52 to 54,
Switchback rollers 55 to 57 and a discharge roller 58 are provided. The switchback rollers 55 to 57 are configured to be rotatable in both forward and reverse directions, and the switchback transport path 61
Is formed. In addition, the sub-transport roller 52 and the discharge roller 58
A flapper 59 is provided between the sub-conveyance roller 54 and the switchback roller 57. The flapper 59 is swingable, and the paper output unit 37
The transfer material discharged from the discharge roller 58 or the sub-conveyance path 62
The flapper 60 that leads to either of the above is also swingable, and guides the transfer material that has passed through the sub-transport path 62 to either the switchback transport path 61 or the cabinet 71.

An intermediate tray 72 is provided inside the cabinet 71. The intermediate tray 72 is provided with paper input rollers 73 to 76, feeding rollers 77 and 78, and flappers 79 to 81. The flappers 79 to 81 are swingable, and those corresponding to the size of the transfer material stored in the intermediate tray 72 swing upward from the state shown in the figure. The sub-conveyance path 62 is extended to the sheet feeding section 31 by the sheet feeding rollers 73 to 76, the intermediate tray 72, and the feeding rollers 77 and 78, and connects the sheet discharging section 37 and the sheet feeding section 31.

As described above, the main conveyance path 42 is formed inside the copying machine main body 21, and the sub-conveyance path 62 is formed inside the double-sided conveyance section 51 and the cabinet 71 mounted on the side surface of the copying machine main body 21. There is. During a normal one-sided copying operation, the paper fed from the paper feed unit 31 passes through the main conveyance path 42, and is ejected from the paper ejection unit 37 via the ejection roller 58 to the outside.

During a double-sided copying operation in which an image is formed on both sides of the transfer material, the transfer material fed from the paper feed section 31 once passes through the copy process section 27 and then from the paper discharge section 37 to the sub-conveyance path 62 and the switchback conveyance path 61. Be led to. After the transfer direction is reversed in the switchback transfer path 61, the transfer material is guided to the intermediate tray 72.
After the document for the back side is set, the transfer material in the intermediate tray 72 is fed by the feed rollers 77 and 78 to the paper feed section 31 and the copy process section 27.
And is conveyed to the copying process unit 27 again by the conveying rollers 38 and 40. At this time, the reverse side of the surface facing the photosensitive drum 22 last time faces the photosensitive drum 22 this time due to the reverse of the transport direction in the switchback transport path 61, and an image is formed on both surfaces of the transfer material. The transfer material on which images are formed on both sides in this way is discharged from the paper output unit 37 through the output roller 58.

During a composite copying operation in which images of a plurality of originals are formed on the same surface of the transfer material, the transfer material that has passed through the copy process unit 27 is directly guided to the intermediate tray 72 from the sub transport path 62. After exchanging originals,
The transfer material stored in the intermediate tray is guided between the paper feeding unit 31 and the copying process unit 27 by the feeding rollers 77 and 78, and is conveyed to the copying process unit 27 by the conveying rollers 38 and 40. At this time, the surface facing the photosensitive drum 22 the previous time also faces the photosensitive drum 22 this time, and images of a plurality of originals are formed on the same surface of the transfer material. The transfer material on which a plurality of images have been formed in this way is ejected from the paper ejection unit 37 via the ejection roller 58 to the outside.

FIG. 3 is a block diagram of a control unit of the image forming apparatus having the above-described multiplex transport function.

On data of the image forming mode key 18, the print switch 19 and the like is input to the CPU 11 from the operation panel control unit 16 via the I / O interface 14. The image formation stop mode key 18 is the mode selecting means of the present invention. The detection data of the detection switch 91 is also input to the CPU 11. The detection switch 91 is provided inside the fixing device 35 and detects the passage of the transfer material. The keys and switch-on data input from the operation panel control unit 16 are stored in the respective memory areas of the RAM 13. The ROM 12 stores a program for calculating the control data of the corner device according to the input data. CPU11 calculates the control data based on the data stored in the memory area of RAM13,
I / O interface 15 to solenoid driver 17,
Output to the copy process control unit 20 and the motor driver 94. The solenoid driver 17 controls the solenoids 1 to 3 on / off based on the control data. In addition, the copying process control unit 20 determines the developing device 24 and the transfer / transfer device based on the control data.
The peeling charger 25 is turned on / off, and the erase lamp 23a is turned on. Motor driver 94
Controls ON / OFF of the main motor 92, the sorter motor 93, and the cabinet motor M.

The solenoids 1 to 3 are flapper 59 and flapper 59, respectively.
The flapper 59 is provided in each of the 60 and the flappers 79 to 81. When the solenoid 1 is turned on, the flapper 59 swings upward and opens in the direction of the sub transport path 62. When the solenoid 2 is turned on, the flapper 60 swings to the left, closing the switchback conveyance path 61 direction and opening the intermediate tray 72 direction. When the solenoid 3 is turned on, one of the flappers 79 to 81 is selectively swung upward to guide the transfer material to the intermediate tray 72. When the single-sided copy mode is selected, the CPU 11 does not output the ON data of the solenoids 1 to 3 to the solenoid driver 17, and the flappers 59, 60, 79 to 81 are in the state shown in FIG. As a result, the transfer material is ejected from the ejection unit 37 to the ejection roller 58.
Be led to.

When the double-sided copy mode is selected, the ON data of the solenoids 1 and 3 is output when the paper is fed from the paper feed unit 31, that is, at the first copying operation. As a result, the flapper 59 swings upward, and the transfer material that has passed through the paper discharge unit 37 is guided to the sub-transport path 62 and the switchback transport path 61 and then stored in the intermediate tray 72. When the transfer material is fed from the intermediate tray 72 in the double-sided copy mode, that is, all the solenoids 1 to 3 are turned off during the second copying operation,
The transfer material is guided from the paper output unit 37 to the output roller 58.

In the composite copy mode, the solenoids 1 and 2 are turned on, and the solenoid 3 is turned on according to the size of the transfer material. This causes the flapper 59 to swing upward and the flapper 60 to swing leftward. Therefore, the sheet that has passed through the sheet discharge section 37 is guided to the intermediate tray 72 from the sub-transport path 62. In the final copying operation in the composite copy mode, the solenoids 1 to 3 are turned off, and the transfer material is guided from the paper output unit 37 to the output roller 58.

When the image formation stop mode key 18 is operated and the image formation stop mode is selected and input, the CPU 11 outputs to the solenoid driver 17 the same data as in the composite copy mode. As a result, the solenoid driver 17 causes the solenoid 1,
2 is turned on, and the solenoid 3 is turned on according to the size of the transfer material. Therefore, the transfer material fed from the paper feeding unit 31 is transferred to the fixing device after the developer image is transferred in the copying process unit 27.
The image is fixed at 35, and is guided from the paper discharge unit 37 to the sub-transport path 62. After this, the transfer material is guided again from the intermediate tray 72 to the copying process unit 27. At this time, the control data in the image formation stop mode is output from the CPU 11 to the copy process control unit 20. As a result, the erase drum 23a is turned on over the entire width of the photosensitive drum 22, and the developing device 24
And the transfer / peel charger 25 is turned off. By this operation, the developer image is not formed on the surface of the photosensitive drum 22, and the developer image is not formed on the surface of the transfer material fed from the intermediate tray 72. During this time, the solenoids 1 to 3 are turned off, and the transfer material that has passed through the fixing device 35 is guided from the paper output unit 37 to the paper output roller 58.

FIG. 1 is a flowchart showing the operation of the image forming apparatus having the above-mentioned multiplex transport function.

When the power is turned on, the memory area in RAM13 is cleared and warming up of the fixing device is started (n1, n
2). After warm-up is completed, the copy data and copy mode settings are input, then the print switch
Wait for operation 19 (n3 to n5). The input copy data and copy mode are stored in the respective memory areas of the RAM 13.

When the print switch 19 is operated, it is determined whether or not the image formation stop mode is set (n6). Image formation stop mode key 18 when using transparencies as transfer materials
To select the image formation stop mode. When the image formation stop mode key 18 is operated during mode setting, the process proceeds to n7, and ON data of each of the solenoids 1 to 3 is output to the solenoid driver 17 (n7). After this OHP
The film is fed from the paper feed unit 31 and the copying process is executed (n8).

When the OHP film that has completed the copying process passes through the fixing device 35 and reaches the detection switch 91, the contents of the counter C are incremented, and the copying process controller 20 turns on the erase data of the erase lamp 23a and the transfer device 24 and the transfer device.
OFF data of peeling charger 25 is output (n9 to n1
1). This n11 is the image formation stopping means of the present invention.
Here, the content of the counter C is checked, and it is determined whether or not it matches the set value A (n12). This set value A
Is the number of times the OHP film is passed through the fixing device 35 in the image formation stop mode, and a predetermined value is stored in the ROM 12 in advance. The OHP film until the set value of the counter C matches the set value of A is the main transport path 42 → the sub transport path 62 →
Intermediate tray → 72 → Copy process unit 27 → Main transport path 42 → Fixing device 35 is repeatedly transported through the course (n12 → n9 → n10 →
n11 → n12). When the content of the counter C matches the set value A, the solenoids 1 to 3 are turned off, the OHP film is guided from the paper output unit 37 toward the discharge roller 58, and is discharged to the outside.
Stop M (n13, n14, n15).

When the image formation stop mode is not selected in n6, the process proceeds to n16, and other processing is performed according to the set mode.

FIG. 4 is a time chart of each device constituting the copying machine having the above-mentioned multiplex transport function.

When the print switch 19 is turned on at time t1, the main motor 92, the sorter motor 93 and the cabinet motor M are driven, and each device of the copying process unit 27 including the developing device 24 and the transfer / peeling charger 25 is driven. Further, the solenoids 1 to 3 are turned on, and either the flappers 59 and 60 and the flappers 79 to 81 operate. When the OHP film on which the developer image is transferred passes through the fixing device 35, if the detection switch 91 is turned on at time t2, the erase lamp 23a is turned on, and at the same time, the developing device 24 and the transfer / peeling charger 25.
Is turned off. Since the main motor 92, the sorter motor 93, and the cabinet motor M are continuously driven, the transparencies are guided to the copying process unit 27 again via the sub-transport path 62. Further, when passing through the fixing device 35, the detection switch 91 is turned on at time t3, the erase lamp 23a is turned off, and the solenoids 1 to 3 are turned off. At this time, the motors 92, 93, M are continuously driven, and the transparencies are ejected from the paper ejection section 37 to the outside via the ejection rollers 58. After that, at a time t4 when a predetermined time has elapsed, the driving of the motors 92, 93, M is stopped and all the operations are completed.

As described above, according to this embodiment, the OHP film on which the developer image is transferred is passed through the sub-conveyance path 62 and is again conveyed to the main conveyance path 42.
To the fixing device 35. Therefore, the OHP film passes through the fixing device 35 twice for one copying process, and the fixing effect of the developer image can be improved. Therefore, it is possible to smooth the surface and prevent irregular reflection of the surface when the image is projected by the projector.

In the present embodiment, a copying machine is taken as an example for description, but the present invention can be similarly implemented in other image forming apparatuses using electrophotography. Further, it can also be used for other transfer materials that require smooth shaping of the image surface. The set value A may be set to 2 or more, and the transfer material may be passed through the fixing device three or more times in one copying process to further improve the fixing effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart showing the operation of a copying machine having a multiplex transport function according to an embodiment of the present invention, and FIG. 2 is a schematic front sectional view showing the construction of the copying machine. FIG. 4 is a block diagram of a control unit of the copying machine, and FIG. 4 is a time chart of each device constituting the copying machine. 27 …… Process section, 31 …… Paper feed section, 37 …… Paper ejection section, 42 …… Main transport path, 62 …… Sub transport path.

Claims (1)

[Claims] 1. An image forming apparatus comprising: a main conveyance path from a paper feed section to a paper ejection section via a process section; and a sub-conveyance path connecting the paper ejection section to the process section. The multi-image forming means for guiding the transfer material that has passed through the sub-passage to the process section again in the same direction to form multiple images, and the transfer material that has passed through the process section in the back side facing again through the sub-transport path. A double-sided image forming unit that guides the image to both sides of the process unit, a fixing number storage unit, and the transfer material that has passed through the process unit is transferred to the process through the number of sub-transport paths stored in the fixing number storage unit. At the same time, the multi-fixing unit that stops the sheet feeding operation and the image forming operation of the process unit during this period and performs only the fixing operation, and one of the multiple image forming unit, the screen image forming unit, or the multiple fixing unit is selected. An image forming apparatus having a multi-carrier function of a mode selection means for, comprising the.