JPS63112340A - Image former - Google Patents

Abstract

PURPOSE:To improve a recording speed without entailing any change in a process speed, by once stopping transfer paper of an image former and, after remedying its delay and skew, installing two sets of stand-by devices for its refeeding, then operating these stand-by devices alternately. CONSTITUTION:A recorder 1 is constituted of a recording part 3 for forming and recording a toner image on a sensitizer drum 2, a transfer paper feeding part 5 for feeding transfer paper 4 successively to the toner image on the sensitizer drum 2 as adjusted to its timing, and a conveying part 6 discharging the transfer paper 4 recorded at the recording part 3 to the specified position, etc. The transfer paper feeding part 5 consists of a paper feed cassette 17 where the transfer paper 4 is housed, a paper feed roller 18, an upper stage stand-by roll pair 19 and a lower stage stand-by roll pair 20 and guide parts 23 and 24. Each of the upper stage stand-by roll pair 19 and the lower stage stand-by roll pair 20 is designed so as to operate the transfer paper 4 fed by the paper feed roller 18 alternately one by one.

Description

DETAILED DESCRIPTION OF THE INVENTION C. Technical Field of the Invention The present invention relates to an image forming apparatus that applies electrophotographic technology, and particularly to an image forming apparatus that has an improved transfer paper feeding section.

[Traditional technique]

2. Description of the Related Art Conventionally, recording devices such as laser beam printers and night crystal printers have been widely used as image forming devices that apply electrophotographic technology.

In such a recording device, if the information processing speed, such as the transfer speed of recorded information from a host etc. or the speed of developing recorded information into a dot pattern within the recording device, is sufficiently high, the recording speed is It mainly depends on process speed.

This process speed is determined by the sensitivity of the photoreceptor, the density of recording dots, the writing speed or light intensity of an optical recording section such as a laser head or a liquid crystal head.

Further, even when the process speed is the same, the recording speed, which is the number of sheets of transfer paper that can be recorded in a predetermined unit time, for example, one minute, is determined by the method of feeding the transfer paper.

[Problems with conventional technology]

The reason why the recording speed of the conventional recording apparatus is determined by the transfer paper feeding method is due to the fact that cut paper (paper that has already been cut to a predetermined size) is used as the transfer paper.

In other words, when cut paper is used, it is difficult to avoid delays or skew that occur irregularly due to slipping when feeding one sheet of transfer paper from a stack of transfer papers, and this delay or skew is difficult to avoid. To correct the line,
It was necessary to use a paper feeding mechanism in which the leading edge of the transferred transfer paper is brought into contact with a correction member such as a standby roll to temporarily stop the transfer paper, and then the stopped transfer paper is conveyed again at a predetermined timing. . That is, extra time was required to control the transfer paper. Therefore, when continuous paper feeding is performed,
A predetermined gap will be created between the first transfer sheet and the next transfer sheet, and the larger this gap, the lower the recording speed will be even at the same process speed.

In other words, in the above-mentioned recording apparatus, although the user can easily process the transfer paper and use the user-friendly cut paper, there is a problem in that the recording speed decreases due to the use of the cut paper.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide an image forming apparatus that can increase recording speed with a simple mechanism at low cost without making major changes such as changing process speed. .

[Key points of the invention]

In order to achieve the above object, the present invention provides an image forming apparatus that forms an image by transferring a toner image formed on the surface of an image carrier onto a transfer paper using a transfer means. At least one paper feeding means that feeds sheets one by one, and two standbys that contact and temporarily stop the transfer paper fed by the paper feeding means and then feed it to the transfer means in synchronization with the toner image. The present invention is characterized in that the apparatus further comprises a transfer paper feeding section having a means, and each of the two standby means is operated alternately for every other sheet of transfer paper fed by the paper feeding means.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings, taking a recording apparatus as an example.

FIG. 1 is a side view of the configuration of a recording apparatus as an image forming apparatus according to the present invention, and FIGS. 2(a) and (b) are detailed side views when the transfer paper feeding section operates for the first time. .

The recording device 1 includes a recording section 3 that forms and records a toner image corresponding to recorded information on a photoreceptor drum 2 as an image carrier, and a recording section 3 that forms and records a toner image corresponding to recording information on a photoreceptor drum 2 as an image carrier, and a recording section 3 that forms and records a toner image corresponding to recording information on a photoreceptor drum 2 as an image carrier. It is composed of a transfer paper feeding section 5 that sequentially feeds the transfer paper 4 at the same timing, and a transport section 6 that transports the transfer paper 4 recorded in the recording section 3 and discharges it to a predetermined position.

The recording unit 3 includes a charger 7 that is disposed close to the circumferential surface of the photoreceptor drum 2 and uniformly charges the photoreceptor drum 2, and a charger 7 that exposes the photoreceptor drum 2 with light according to recording information. A print head 8 that forms an electrostatic latent image, a developer 9 that develops the electrostatic latent image formed on the photoreceptor drum 2 with toner to form a toner image, and transfers the toner image onto the transfer paper 4. The transfer device 10 includes a cleaner 11 that removes residual toner on the photosensitive drum 2 that has not been transferred by the transfer device 10. The print head 8 consists of a fluorescent lamp 12 as a light source, a liquid crystal light shutter 13 which is a collection of many microshutters that open and close according to recording signals, and an imaging lens array 14, The light that has passed through the micro-shutter in the open state is formed into an image on the photosensitive drum 2 by the imaging lens array 14 to form an electrostatic latent image.

The conveyance section 6 transfers the toner image on the photoreceptor drum 2 to a transfer device 10.
Transfer paper 4 that has been transferred and separated from the photosensitive drum 2
It is comprised of a guide vi, 15 that receives and guides the image, and a fixing roll 16 that fixes the recorded information after being transferred by heat and pressure.

The transfer paper feeding section 5 includes a paper feed cassette 17 that stores transfer papers 4 of a predetermined size in a stacked manner, and a paper feed cassette 17 that takes out and feeds the transfer paper 4 one by one starting from the top one. Coro 18
, an upper standby roll pair 19, a lower standby roll pair 20, a guide means for guiding the transfer paper 4, and the like.

The paper feed cassette 17 includes a case 17a provided with a presser plate 17c that is biased by a spring 17b.
A large number of transfer papers 4 are stored in a stacked manner on the paper 7c. The paper feed roller 18 is disposed above the transfer paper 4 on the leading end side of the paper feed cassette 17, is supported by the paper feed shaft 18b via a one-way bearing 18a, and is attached to the uppermost transfer paper 4 by the biasing force of the spring 17b. are in contact. Paper feed shaft 18
b is rotated clockwise in FIGS. 1 and 2 by a drive source (not shown), and this rotation also rotates the paper feed roller 18 in the same direction, so that the transfer paper 4 in the paper feed cassette 17 is transferred one sheet at a time. Sent out. The paper feed roller 18 is set at a higher speed than the circumferential speed of the photoreceptor drum 2. A light emitting element 21 and a photosensor 22 are provided at the upper and lower parts near the tip of the paper feed cassette 17, and the paper feed sensor composed of the light emitting element 21 and the photosensor 22 causes the paper to be sent out from the paper feed cassette 17. The passage of the transfer paper 4 is detected. The upper standby roll pair 19 and the lower standby roll pair 20 are arranged one above the other in the vicinity of the photoreceptor drum 2 on which a toner image is formed, and are each driven via separate standby clutches (not shown). Further, between the upper standby roll pair 19 and the lower standby roll pair 20 and the front end side of the paper feed cassette 17, there is a transfer paper 4 fed out from the paper feed cassette 17.
An upper guide section 23 and a lower guide section 24 are provided to guide the guides, respectively. The upper guide section 23 is formed of guide plates 23a and 23b that are slightly wider on the paper feed cassette 17 side and narrower toward the upper standby roll pair 19 side.Similarly, the lower guide section 24
, the paper feed cassette 17 side is slightly wider than the lower standby roll pair 2.
It is formed of guide plates 24a and 24b that become narrower toward the 0 side. Near the pair of standby rolls (19 and 20) of the upper guide part 23 and the lower guide part 24, there are upper and lower standby sensors 25 and 2, respectively, which are comprised of reflective photosensors.
6 are provided, and the passage of the transfer paper 4 is detected by the upper and lower standby sensors 25 and 26. Further, the upper guide part 23 and the lower guide part 24 each have a standby roll pair (19
and 20) It is provided so as to be rotatable around the vicinity, and the transfer paper 4 is guided to the upper guide part 23 in the upper stage position shown in FIG. The lower position shown in FIG. 2(b) is movable by driving a solenoid or the like (not shown). That is, the upper guide section 23, the lower guide section 24, and the solenoid constitute a guide means for selectively guiding the transfer paper 4 to the upper standby roll pair 19 and the lower standby roll pair 20. The upper standby roll pair 19 and the lower standby roll pair 20 are roll pairs that are rotated and stopped, respectively, by a control means (not shown), and the transfer paper 4 sandwiched and conveyed by these roll pairs.
is guided to the transfer section by the guide section 27. Guide section 27
a guide plate 27a that guides between the upper standby roll pair 19 and the lower standby roll pair 20 and the transfer portion of the photoreceptor drum 2;
It is formed by 27b and 27c.

Next, we will discuss the paper feeding operation of the recording apparatus 1 with the above configuration. The case where three sheets of transfer paper 4 are fed will be described as a representative example.

At the start of operation, each guide section 23 and 24 is in the position shown in FIG. 2(a).
The paper feed roller 18 first starts rotating, and the first sheet of transfer paper 4 located at the top of the paper feed cassette 17 is sent out. This transfer paper 4 blocks the light from the light emitting element 21, so that the paper feed sensor is turned on, but the control state remains unchanged. The transfer paper 4 passes between the guide plates 23a and 23b of the upper guide section 23, and the lower standby sensor 25 is turned on. After a predetermined period of time has passed after the lower standby sensor 25 is turned on, the rotation of the paper feed roller 18 is stopped. Within this predetermined time, the leading edge of the transfer paper 4 reaches the pressure contact part of the stopped upper standby roll pair 19, and the paper feed roller 18 rotates and stops until a short time elapses. The transfer paper 4 forms a loop-shaped deflection, and due to the stiffness of the transfer paper 4 due to this deflection, the leading edge of the transfer paper 4 comes into contact with the above-mentioned pressing portion with a predetermined pressure. Next, based on a specified timing signal from the print head 8, the upper standby roll pair 19 starts rotating.

The predetermined timing is the timing when the leading edge of the toner image on the photosensitive drum 2 coincides with the leading edge of the transfer paper 4. Due to the rotation of the upper standby roll pair 19, the transfer paper 4 that was in contact with the pressure contact portion is held between the upper standby roll pair 19,
It is transported to the guide section 27. The conveyance speed of the upper standby roll pair 19 is the same as that of the photoconductor drum 2, and the leading edge of the conveyed transfer paper 4 coincides with the leading edge of the toner image formed on the photoconductor drum 2, and this toner image is transferred onto the transfer paper 4. When conveying the transfer paper 4, the paper feed roller 18 is dragged by the transfer paper 4 and rotates, but this rotation is stopped due to the presence of the one-way bearing 18a on the paper feed shaft 18b.
The paper feed rollers 18 do not become a load for conveyance. Next, the rear end of the transferred transfer paper 4 pulls out the paper feed cassette 17, advances further, and reaches the light emitting element 21.
When the light from the photo sensor 22 is no longer blocked and the paper feed sensor is turned off, a solenoid (not shown) is activated and each guide portion 23 and 24 is rotated to the lower position shown in FIG. 2(b). At the same time, movement of the paper feed roller 18 is started. As a result, the second sheet of transfer paper 4 passes between the guide plates 24a and 24b of the lower guide section 24 after turning on the paper feed sensor. After the second sheet of transfer paper 4 turns on the lower stage standby sensor 26, the paper feed roller 18 continues to rotate for a predetermined time and then stops. At this time, as in the case of the upper stage position described above, the second sheet of transfer paper 4 is bent in a loop shape, and the leading edge of the second sheet of transfer paper 4 is connected to the lower standby roll pair.
It is in contact with the pressure contact part of 0. Further, when the paper feed roller 18 stops in this manner, the rear end portion of the first transfer paper 4 has not passed the upper stage standby sensor 25 and is in a conveying state. Immediately after the rear end of the first sheet of transfer paper 4 passes the upper standby sensor 25 and the pair of upper standby rolls 19, a second predetermined timing signal is sent from the print head 8. By this timing signal, the lower standby roll pair 20
starts rotating, and the second sheet of transfer paper 4 is pinched and conveyed.

The above operation makes it possible to extremely reduce the distance between the rear end of the first transfer paper 4 and the leading end of the second transfer paper 4 in the transfer section.

Furthermore, when the rear end of the second sheet of transfer paper 4 turns off the paper feed sensor, a solenoid (not shown) is activated to return each guide section 23 and 24 to the upper position, and the paper feed roller 18 rotates to The first sheet of transfer paper 4 is sent out. The same operation is performed below.

In the above embodiment, there is one paper feed roller 18, but the paper feed force may be set in two stages, and the paper feed roller 18 may be provided for each paper feed cassette. Any configuration that can selectively switch and guide the two upper and lower standby rolls 19 and 20 is sufficient. Furthermore, the spacing between the transfer sheets 4 can be arbitrarily adjusted by a timing signal from the print head 8 to the extent that they do not overlap.

In addition, the arrangement of the paper feed cassette 17, the guide section 23, 24, 27
The shape of is not limited to that of the embodiment, but can be any shape. Moreover, the upper and lower standby roll pairs 19 and 20 may be standby means other than rolls.

〔Effect of the invention〕

According to the present invention, two sets of standby means are provided for once stopping the transfer paper and feeding it again after correcting the delay or skew due to slipping, and by operating the standby means alternately, the paper can be continuously fed. Since the spacing between the transfer sheets is extremely small, the recording speed can be increased at low cost with a simple mechanism without changing the process speed.

[Brief explanation of the drawing]

FIG. 1 is a side view of the configuration of the recording apparatus of this embodiment, and FIG.
) is a detailed side view of the transfer paper feeding unit showing the state in the upper stage position in Fig. 1, and Fig. 2(b) is a detailed side view of the transfer paper feeding unit showing the state in the lower stage position in Fig. 1. . DESCRIPTION OF SYMBOLS 1... Recording device, 2... Photosensitive drum, 3... Recording section, 4... Transfer paper, 5... Transfer paper feeding section, 6... Conveying section, 7... Charger, 8...Print head, 9...Developer, 10...Transfer device, 11...Cleaner, 12...Fluorescent lamp, 13...Liquid crystal light shifter, 14...Result Image lens array, 15... Guide plate, 16... Fixing roll, 17... Paper feed cassette, 17a... Case, 17b... Spring, 17c... Holding plate, 18... Feeding Paper roller, 18a... One-way bearing, 18b... Paper feed shaft, 19... Upper standby roll pair, 20... Lower standby roll pair, 21... Light emitting element, 22... Photo sensor, 23.24...Guide part, 23a, 23b, 24a, 24b... Guide plate, 25.26... Standby sensor, 27... Guide part, 27a, 27b, 27c... Guide plate.

Claims (2)

[Claims] (1) In an image forming apparatus that forms an image by transferring a toner image formed on the surface of an image carrier onto transfer paper using a transfer means, at least one unit feeds a large number of stacked transfer papers one by one. A transfer paper feeding unit comprising a paper feeding unit, and two standby units that abut the transfer paper fed by the paper feeding unit and temporarily stop the paper, and then send it out to the transfer unit in synchronization with the toner image. An image forming apparatus characterized in that each of the two standby means is operated alternately for every other sheet of transfer paper fed by the paper feeding means. (2) The transfer paper feeding section includes the single paper feeding means and a guide means for alternately guiding every other sheet of transfer paper fed by the paper feeding means to each of the two waiting means. An image forming apparatus according to claim 1, characterized in that the image forming apparatus has: