JPH03129374A - Electrophotographic printer device - Google Patents

Abstract

PURPOSE:To correct skew and to eliminate folding fault by controlling the press-contact of rollers in a fixing unit in specific positional relation to the machine-sewed perforation of continuous paper. CONSTITUTION:According to a detecting signal when a detecting means M detects the previous perforation or to a detecting signal when the detecting means M detects the following perforation, a control means C gives a driving signal to the driving source of a contact/uncontact means S to drive the means when perforations get to the vicinity of the press-contact point of rollers 5 and 6 in a fixing part. A cam 10 rotates to get its upper part to a roller 9, and a lever 7 turns counter clockwise around a shaft 8. Consequently, the roller supported by the lever 7 separates from the roller, and therefore a non-heat fixing area NFA is formed between heat fixing areas FA around the perforation Sl. Whenever one page is fixed, the roller in the fixing unit is separated, during which the skew of the carried paper is corrected. Thus, the bending of perforation ad the skew of paper are corrected.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an electrophotographic printer that uses continuous paper having creases such as perforations, and more particularly to an electrophotographic printer that transports the continuous paper with a tractor provided between a photosensitive drum and a fixing device.

[Prior art]

Generally, high-speed printers used as output devices for computers and the like use continuous paper that is folded with creases such as perforations (hereinafter referred to as perforations) in the lateral direction at every fixed length of the paper. If this printer is an electrophotographic type, the output information from the computer is converted into a latent image on the photoreceptor using an exposure device.
Toner is attached to the photoconductor using a developing device and developed, and then the toner is transferred onto continuous paper using a transfer device to visualize characters, figures, etc., and then the toner on the continuous paper is fixed using a fixing device. let Generally, in a printer using continuous paper, a tractor is provided between the photosensitive drum and the fixing device, which constantly engages with the feed hole of the paper to apply a conveyance force. In addition, a pair of rollers that make up a conventional fuser are placed above and below the paper conveyance surface, but these rollers are always in pressure contact, so each page of continuous paper that is conveyed while printing is Continuously pressurized and heated.

[Technical problem to be solved]

However, when fishing on a boat, the paper contains a small amount of water. As mentioned above, when printing multiple pages continuously, with a conventional fuser, all of the pages are continuously fed through pressure between the upper and lower rollers of the fuser, which causes the fuser to heat up. In the case of the fixing method, the continuous paper is fed between the upper and lower heating rollers and pressure rollers at a high temperature of about 120"C, which causes the paper to spread out. Also, the rollers of the fixing device It is inevitable that the diameter will have some error (manufacturing error) in the axial direction, therefore,
During continuous conveyance of paper during printing, a skew <m feed line mis> occurs in the continuous paper between the tractor and the fixing device, resulting in wrinkles on the paper, and the heat and pressure of the fixing process removes the wrinkles. is solidified. When these hardened wrinkles occurred at the perforations, they acted as ribs and caused problems in folding the paper after fixing. Furthermore, when the skew increases, a misalignment occurs between the tractor bin and the paper feed hole, which leads to damage to the feed hole and, eventually, to paper jamming. Conventionally, to solve the problem of skew occurrence as described above,
It was equipped with a skew correction roller that tightened the slack in the continuous paper. In addition, in order to deal with folding failures, the paper was equipped with a folding device that forcibly folds the continuous paper after fixing. Therefore, the configuration becomes complicated and the cost becomes high. In an electrophotographic printer that includes a tractor between a photosensitive drum and a fuser and uses continuous paper having perforations, the roller of the fuser comes into pressure contact with the perforations of the continuous paper in a specific positional relationship. An object of the present invention is to correct the skew and eliminate folding obstacles without providing a skew correction roller or a folding device.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an electrophotographic printer device that includes a tractor between a photosensitive drum and a fixing device, and uses the tractor to transport continuous paper having perforations. means for detecting a perforation; a contact/separation means for bringing the rollers of the fixing device into pressure contact with each other and separating them; The fixing apparatus is characterized by comprising a control means for driving the contact/separation means to separate the rollers when the fixing device reaches near a roller pressure contact point of the fixing device. Further, a means for detecting a perforation in the continuous paper being conveyed and a folding direction of the perforation, a contact/separation means for bringing the roller of the fixing device into pressure contact with or separating it from each other, and a means for detecting the perforation by the detection means. Based on the detection, if one of the mountain fold and the valley fold is detected, the roller of the fixing device is separated from the end of the print area of the previous page to the perforation, and the other of the mountain fold and the valley fold is detected. The present invention is characterized by comprising a control means that, when detected, moves the roller of the fixing device away from the print area of the immediately previous page, beyond the fold line, to the starting edge of the print area of the next page.

[Effect]

With the above configuration, in the printer device according to the present invention, based on the detection means detecting the perforation of the continuous paper, the perforation portion approaches the pressure contact point of the roller of the fixing unit until it reaches a predetermined position. , the control means drives the contact/separation means to separate the rollers of the fixing device. When one of the mountain fold part and the valley fold part approaches the roller pressure contact point of the fixing device, the control means C drives the approach and separation means between the end of the print area and the perforation of the print area of the previous page, and the fixing Separate the rollers of the container. When the other of the mountain fold part and the valley fold part approaches the roller pressure contact point of the fixing device, the control means C controls the approach and separation means between the end of the print area of the previous page and the start of the print area of the next page. to separate the rollers of the fixing device.

【Example】

Next, embodiments of the present invention will be described based on the drawings. FIG. 1 is a sectional view showing a schematic configuration of an electrophotographic printer. In the figure, reference numeral 1 denotes a continuous sheet of paper, and as in conventional printers of this type, a conveyance control unit (not shown) controls a conveyance control unit to move the paper to a first tractor 2 and a second tractor 3.
is driven and transported in the direction of the arrow through the transport guide 4. The m-feed control unit controls the tractor when the paper is initially loaded, when the paper is ejected due to paper consumption, when a page is changed, etc., and when printing is performed based on the output from the computer. 2 and 3 are driven. Further, K in FIG. 1 is a transfer unit that visualizes computer output information on continuous paper 1 using an electrophotographic method. 23, a transfer device 24, and a cleaning device 25, and a fixing device T for fixing the toner transferred to the continuous paper is provided behind the transfer section. The fixing device T includes rollers 5 arranged above and below the paper transport surface.
, 6. When the fixing device is of a heat fixing type, the upper roller 5 is a heating roller, and the lower roller 6 is a pressure roller. , the upper and lower rollers 5 and 6 are pressure rollers. Control of the transfer process in the transfer unit K, control of conveyance of the continuous paper 1 to the transfer position corresponding to the transfer process, and control of the paper against the photosensitive drum by a paper guide means to prevent damage due to contact with the circumferential surface of the photosensitive drum. The separation motion and the contact motion are controlled in the same manner as in the past. In the electrophotographic printer according to the present invention, the fixing device T is provided with contact/separation means S for separating or pressing the upper and lower rollers 5.6. This contact/separation means is
A lever 7 is rotatably supported at one end with a shaft 8 as a fulcrum, the roller 6 is supported at the other end of the lever, and a roller 9 is rotatably provided in the middle of the lever 7. A cam 10 corresponding to the circumferential surface of the roller 9 is provided above the paper conveyance surface, the lever 7 is always urged upward by a spring 11, and a drive source (not shown) is connected to the rotation shaft of the cam 10. It is composed of The drive source may include, for example, a rotary solenoid or a motor that rotates 90" when energized, and a motor control circuit that rotates the motor until the cam 10 is rotated 90 degrees each time a drive signal is input. As shown in FIG. 2, the cam 10 is normally held in a state where the lower part of the cam 10 is in contact with the roller 9, so that the roller 6 is in pressure contact with the roller 5. but,
When the drive source is driven by the control means C described later, the cam 10 is rotated by 90 degrees and its high portion comes into contact with the roller 9, so that the roller 6 is separated from the roller 5 as shown in FIG. . In the figure, M is a detection means for detecting perforations in the continuous paper being conveyed, and it is composed of a photoelectric element 12, etc., and if the printer device is equipped with an automatic paper loading function, it is installed in the transfer section. The continuous paper leading edge detection unit provided in front of the paper also serves as the detection means. However, f of the detection means M
The iW position is not particularly limited. Reference numeral C denotes a control means for operating the driving source of the approaching and separating means S based on the detection output of the detecting means M. As shown in FIG. 4, this control means C includes a CPU, ROM, and RA.
M, the CPU is configured by a microcomputer having the detection means M, 1! through an interface (Ilo). It is connected to the feeding means T and the contact/separation means S. The timing at which the drive source is controlled based on the perforation detection output is determined by the installation position of the detection means M, the distance between the perforations of the continuous paper, the setting range of the non-fixing area, and the paper conveyance step management. be done. The distance between perforations of the continuous paper used is determined in advance by paper manufacturing standards. Further, the distance from the mounting position of the detection means M to the pressure contact point of the rollers 5 and 6 is predetermined. Therefore, after the perforation (leading edge) of the continuous paper being conveyed is detected by the detection means M, the timing when the perforation reaches the roller pressure contact point of the fixing device is determined by step management of paper conveyance (driving of the conveyance means). It can be easily measured by counting and managing the pulses given to the stepping motor to transport the paper. 11JIII means C measures the timing when the perforation reaches the vicinity of the pressure contact point of the fixing section based on the input of the detection signal from the detection means M, and at that timing, the approaching and separating means S
A control signal is given to the drive source to drive it for a predetermined period of time,
The roller 6 is separated from the roller 5. With the above configuration, the leading end of the continuous paper is now set on the first tractor 2, and the paper feed command switch (not shown) is turned on.
Then, the control means C drives the drive unit of the conveyance means T, so that the continuous sheet of paper is conveyed in the direction of arrow A in FIG. When the copy is conveyed to the position corresponding to the print start position, if the combiator is ready to output printing information to the transfer section K, printing based on that output information is started and conveyance of the paper is continued. Ru. However, if the computer is not ready to output print information to the transfer section, transportation is stopped and a print request from the computer is waited for. The continuous sheet of paper that has completed the transfer process by the transfer unit K is further conveyed by the second tractor 3 that is rotating in synchronization with the first tractor 2, and is conveyed to the fixing unit for the next process.
In this fixing section, heat and pressure are applied by upper and lower rollers 5 and 6 that are in pressure contact with each other to fix the toner on the continuous paper. A detection signal outputted when the detection means M detects the previous perforation due to the conveyance of the continuous paper accompanying the printing,
Or, based on the detection signal output when the next perforation is detected, the control means C controls whether the perforation is detected by the roller 5□6 of the fixing section.
When the cam reaches the vicinity of the pressure contact point, that is, between the end of the print area of the page and the start of the print area of the next page, a drive signal is applied to the drive source of the contact/separation means S to drive it. When the lever 10 rotates and the high portion of the cam faces the roller 9, the lever 7 rotates counterclockwise in FIG. 3 about the shaft 8. Therefore, since the roller 6 supported by this lever 7 is separated from the roller 5,
As shown in FIG. 5, a non-thermal fixing area NFA is formed between the thermal fixing area (print area) FA before and after the perforation S1. Since the rollers of the fixing device are separated each time one page is fixed, the paper conveyance skew is corrected during that time. In addition, in the case of the heat fixing method, if a paper presser piece 13 is provided at the tip of the lever 7 and is bent in a direction perpendicular to this, the paper presser piece 13 can be
3 separates the continuous paper 1 from the heat roller 5, so that heat is not transferred to the perforations. Therefore, the perforations of the paper are not hardened by heat and the bending tendency is not attenuated, and the paper is Burning and deformation of the heating roller and pressure roller are prevented. After the perforation passes the detection means M, the control means C stops the driving of the approaching and separating means, so the cam 10 is rotated again by a predetermined amount, and the lower part of the cam faces the roller 9, and the roller 5 and 6 return to the state where they are in pressure contact again, so as long as the output information from the computer continues, the detection means M, control means C, and approach/separation hand FIS will perform the fixing described above for each perforation as the paper is conveyed. Temporary opening and closing of the section is repeated. In the above embodiment, since the paper leading edge detecting section is also used as the detecting means M, the drive control of the approaching/separating means S is performed based on the conveyance step management based on the detection signal from the detecting means M. When the means is provided close to the fixing device, the approaching/separating means can be directly controlled based on the detection signal of the detecting means. Furthermore, although the approaching/separating means S is configured to move the lever 7 using the cam 10, the means for separating the roller 6 from the roller 5 is not limited to this, and Ike's well-known technique can be used. However, as mentioned above, if the area from the end of the print area of the immediately preceding page to the start of the print area of the immediately following page is set as a non-fixing area for each perforation, the skew correction effect can be reliably obtained; Compared to the fixing area, the area still contains moisture and is weak, so depending on the quality of the paper, it may pass through the fixing device and be transported to the continuous paper stacking position, as shown in Figure 6. Furthermore, a large number of wrinkles SHR that bridge the front and rear sides of the perforation are likely to occur in each non-fixing area NFA, and such wrinkles may act as ribs and impede folding. The present inventors have conducted various studies on the timing for separating the rollers of the fixing device so that the skew is corrected and the creases at the perforations are not attenuated. FIG. 7(a) is a perspective view showing the first plan of the first comparative example;
Figure (b) is a perspective view of a main part explaining the second plan. In the first comparative example, the control unit C controls the pressure roller from the time when the end of the printing area of the continuous paper 1 reaches the pressure contact point of the roller of the fixing device to the time when the point immediately before the perforation reaches the pressure contact point by controlling the conveyance step. 6 is separated from the heating roller 5. In the second plan, from the time when the perforation of the conveyed continuous paper 1 passes the roller pressure contact point until the end of the transfer area t11 of the next page reaches the pressure contact point, the pressure p-ra 6 is moved to the heating roller 5.
The control means C is configured so as to be spaced apart from. When the above range is set as the non-fixing area NFA, the separation time is extremely short compared to the high paper conveyance speed, so the skew is not sufficiently corrected. In the case of the above-mentioned first comparative example, since the distance between the perforation and the transfer area is required, it is difficult to adopt it when the distance between the transfer area and the perforation is small. In other words, if a non-fixing area is secured, the printing area may be restricted. In the second comparative example, skew correction can be performed without taking up the unfixed area, wrinkles can be prevented, and the printing area can be expanded. In order to achieve such R performance, in the second comparative example, the control means C was configured as follows. That is, as shown in FIG. 8(a), in the first plan, thermal fixing F1 is performed until the perforation of the paper passes the roller pressure contact point by controlling the conveyance step and the contact/separation means, and then the pressure contact point is Once the paper has passed, the pressure roller is separated to stop fixing, and then the conveyance means is reversed to convey the continuous paper a predetermined distance from the above-mentioned stopping position to a position that does not exceed the perforation.
The pressure roller is pressed again to convey the paper in the forward direction and heat fixing F2 is performed. As a result, in the area indicated by symbol W in FIG. 8(a), heat fixing Fl and F2 of the previous and following pages overlap. do. Therefore, since the perforation portion is thermally fixed, the generation of wrinkles is prevented, and the pressure roller is temporarily separated at a position beyond the perforation, so that the skew is corrected. Furthermore, since fixing for the print area of the next page is started after the paper is reversely conveyed to the vicinity of the perforation, the print area is not restricted. In the second plan of FIG. 8(b) and the third plan of FIG. 8(e), (a)
In the same way, the fixing area is thermally fixed up to the perforation, and the fixing area is overlapped at a position that avoids the perforation, but (b) is fixed up to just before the perforation (Fl).
After the paper is once transported backwards by a predetermined amount, it is transported forward again and at the same time, fixing (F2) is performed. In (C), fixing (F1) is performed up to the perforation, and
4. In either case, wrinkles are prevented from forming at the perforations, and
Narrowing of the transfer area is prevented or it becomes possible to expand the transfer area. However, the processing speed in the case of continuous printing decreases. The present inventors believe that, based on the above-mentioned basic idea of separating the rollers of the fuser near the perforations of continuous paper, skew correction is sufficiently performed and folding performance, especially at mountain folds, is improved. Furthermore, as a result of various experiments conducted in search of the best control mode that would not cause a decrease in the processing speed of continuous printing, it was found that the detector ViM and the control means C are optimally configured as follows. I discovered something. That is, the detector fiM in FIG. 4 is one that has the function of detecting perforations in continuous paper and the function of detecting whether the perforations are mountain folds or valley folds. As such a means for detecting the perforation fold direction of continuous paper, the one disclosed in Japanese Patent Application Laid-Open No. 2-13558 by the applicant of the present invention can be used. However, the method for detecting mountain folds and valley folds is not limited to mechanical and electrical detection, and photoelectric detection is also possible. Then, as shown in FIG. 8, the control means C shown in FIG. From the time when the perforation reaches the pressure contact point or just before that, more precisely from the end of the printing area PA of the page immediately before the perforation of the mountain fold to the perforation s1m, the contact/separation means S is driven to separate the rollers, and based on inputting a valley fold detection signal from the detector PiM, the perforation slv of the valley fold reaches the vicinity of the pressure contact point of the fixing device. The approach/separation means S is driven to move the rollers away from each other until the beginning of the print area PA of the next page. In this way, in mountain folding, the area from the end of the print area of the page immediately before the perforation to the perforation is the non-fixed area N
FAI, and in valley folding, by setting the area from the end of the print area of the page immediately before the perforation to the start of the print area immediately after the perforation as the non-fixing area N F A 2,
Not only is the crease at each perforation not attenuated, but in the mountain fold area, the area immediately after the perforation removes moisture and hardens the paper by fixing, so the dead weight of the *a paper that falls after printing is completed causes The perforation has the characteristic of being easily folded when subjected to a force in the direction of mountain folding. In addition, in valley folding, the non-fixing area NF has a relatively large width from the end of the print area to the start of the page before and after the perforation.
Since A2 is secured, even if the paper conveyance speed of a high-speed printer is high, the skew that may occur due to continuous conveyance of each page can be sufficiently corrected. Even in this valley folding, the folding tendency is not attenuated, so the folding can be done easily. Depending on the thickness of the paper, the relationship between the width of the non-fixing area and the folding direction of the paper may be reversed from the above example.

【Effect of the invention】

As explained above, according to the first invention, the rollers of the fixing section are separated when the perforation reaches the vicinity of the pressure contact point of the fixing section based on the detection of the perforation. Attenuation of the tendency of the eye to bend is prevented, and the skew of the paper is corrected. Therefore, there is no need to provide a skew correction roller, a post-fixing folding device, etc. unlike the conventional method. Further, according to the second invention, in either a mountain fold or a valley fold, fixing is stopped from the end of the printing area of the immediately preceding page to the perforation, so that the folding tendency due to the fixing of the perforation is attenuated. Not only is this prevented, but the hardening immediately after the perforation makes it easier to fold the paper. Further, in the other of the mountain fold and the valley fold, a non-fixing area is secured before and after the perforation, so that the conveyance skew can be reliably and sufficiently corrected even in a printer having a long conveyance speed.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an embodiment of the present invention, FIG. 2 is a surface diagram showing an example of the structure of the approaching and separating means, FIG. 3 is a curved view showing the operating state of the approaching and separating means, and FIG. The figure is a block diagram showing the electrical configuration of the control means, FIG. 5 is a perspective view showing an example in which a non-fixing area is provided on a continuous sheet of paper based on the first invention, and FIG. 6 is a diagram showing wrinkles generated in the non-fixing area. FIG. 7 is a perspective view showing an example of the state, and FIG. 7 is a perspective view showing the positional relationship between the fixing area and the non-fixing area according to the first comparative example. FIG. 8 shows the positional relationship between the fixing area and the perforation according to the second comparative example, and FIG. 9 shows an example in which a non-fixing area is provided on continuous paper based on the second invention. FIG. DESCRIPTION OF SYMBOLS 1... Continuous paper, 2... First tractor, 3... Second tractor, 4... Guide member, K... Transfer section, T... Fixing device, 5.6. ...roller, M...detection means, C...control means, S...! #Release means, 7... Lever 8... Shaft, 9... Roller, 10... Cam, 11... Spring, sl... Perforation, FAI, FA2. FI NFA...Non-fixing area. F2...fixing area,

Claims (2)

[Claims] (1) In an electrophotographic printer device that includes a tractor between a photosensitive drum and a fixing device, and in which the tractor conveys continuous paper having creases such as perforations, (a) the folds of the continuous paper being conveyed are (b) a means for bringing the rollers of the fixing device into pressure contact with each other and separating them from each other; (c) detecting the folds of the continuous paper being conveyed based on the detection of the folds by the detection means; An electrophotographic printer apparatus comprising: a control means for driving the contact/separation means to separate the roller when the fixing device reaches a roller pressure contact point. (2) In an electrophotographic printer device that includes a tractor between a photosensitive drum and a fixing device, and in which the tractor conveys continuous paper having folds such as perforations, (a) folds and creases of the continuous paper being conveyed; (a) a means for detecting the folding direction of the fold; (b) a contact/separation means for bringing the rollers of the fixing device into pressure contact or separating them; (c) based on the detection of the fold by the detection means; (a) When one of the mountain fold and the valley fold is detected, the roller of the fixing device is separated from almost the end of the printing area of the immediately preceding page to the fold; (b) when the other of the mountain fold and the valley fold is detected; an electronic photograph, comprising: control means for separating the roller of the fixing device from approximately the end of the printing area of the immediately preceding page to almost the beginning of the printing area of the next page beyond the crease; type printer device.