JPH0455256A - Image forming device - Google Patents

Abstract

PURPOSE:To reduce waiting time by detecting the position of a paper sheet in transfer and varying the transfer speed of the paper sheet after a fixing means in the detection. CONSTITUTION:A paper sheet P is sent from a tray 16 with a paper ejecting roller 5, and its front edge is aligned in a resist roller 6, and a toner picture is transcribed on the paper sheet P in a photosensitive material drum 8. Then the paper sheet P is sent to a fixing roller 10 with transfer guide rollers 7, 9, and sent to an ejection roller 11 after fixing the picture. A paper sensor 21 is provided on the convey channel just behind the fixing roller 10. When the front edge of the paper sheet P is detected, the output signals of the sensor 21 are changed to a low level output signal from a high level and transmitted to a controller 1, and it is recognized that the paper sheet P is passing through the fixing roller 10. When the rear edge of the paper sheet P is detected and the output signals are changed to the high level, the ejection roller 11 is rotated at a high speed to send the paper sheet P to a tray 12 speedily. Thereby the transfer speed of the paper sheet P can by increased on the way to reduce actual waiting time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus that forms an image based on data.

[Prior Art] Conventionally, a laser printer as an image forming apparatus has been configured as shown in FIG. In this laser printer, when performing a printing operation, the controller 1
A signal is sent to the main motor controller 2, and the main motor controller 2 drives the main motor 3. The power generated by the main motor 3 is transmitted to each roller (6 to 11) by a power transmission device 4 such as a gear.

Then, when the paper sensor 15 in the paper feed tray detects that there is paper P in the paper tray 16, the controller 1 controls the paper feed clutch 13 to transmit the power from the main motor 3 to the paper feed roller 5. Switch like this. The paper feed roller 5 feeds the paper P from the paper tray 16 toward a pair of registration rollers 6. The leading edge of the paper P is adjusted by the registration rollers 6, and then sent to the next developing section. Further, in the developing section, the toner image developed on the photoreceptor drum 8 is transferred onto the paper P, which is then sent to the fixing section by the conveyance guide roller 7.9. In the fixing section, the toner on the paper P is melted by a pair of heated fixing rollers 10 and is attracted to the paper P. The sheet P that has been fixed (on which a printed image has been completed) is sent to a pair of ejection rollers 11, and further sent to a paper ejection tray 12 by the ejection rollers 11.

At this time, the paper feeding speed from the paper feed roller 5 to the paper ejection roller 11, that is, the paper feeding speed from paper feeding to paper ejection was constant.

[Problems to be Solved by the Invention] However, even after the trailing edge of the paper P passes the fixing roller 10 and there is no need to process the paper P anymore, the ejection roller 11 continues at the same speed as before. Due to the rotation, the discharge speed was constant. As a result, users who use the laser printer may find the waiting time from when the leading edge of the paper begins to appear until the trailing edge of the paper is ejected to be longer than usual, which may be uncomfortable, such as when they want to check the printing results as soon as possible. There was a problem that it felt like

The present invention has been made to solve the above-mentioned problems, and reduces the user's discomfort by changing the paper conveyance speed from when the leading edge of the paper begins to be seen until the paper is ejected. An object of the present invention is to provide an image forming apparatus that can perform the following functions.

[Means for Solving the Problems] In order to achieve this object, the image forming apparatus of the present invention has the following features:
A detection means for detecting the position of the sheet conveyed by the conveyance means and a detection signal from the detection means have a constant value of 41.
The present invention is characterized by comprising a conveying speed changing means for changing the conveying speed of the conveying means subsequent to the conveying means '1'.

Note that it is also possible for this detection means to detect the trailing edge of the paper.

[Function] The present invention having the configuration described in -1- has the following features in the developing means:
An image is formed on the paper conveyed by the conveyance means based on data input manually by an external data input device or the like. The sheet of paper on which this image has been formed is further conveyed by a conveyance means to a fixing means, and the unfixed images are successively fixed on the sheet of paper.

At the same time as the paper is fixed, it is ejected by the conveyance means. The detection means detects the position of this paper and sends a paper detection signal -J to the conveyance speed changing means. Immediately after the sheet passes through the fixing means, the conveying speed changing means changes the conveying speed of the conveying means after the fixing means, and changes the subsequent ejection speed of the sheet.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration diagram of a laser printer according to an embodiment of the present invention. In the order in which the sheets are conveyed, a paper feed tray 16 that supplies paper I), a paper feed l/ray sensor 15 that detects the presence or absence of paper P in the paper feed l/ray 16, and a paper feed tray 16. A paper feed roller 5 is provided for taking out the paper P from the paper. Further, on the downstream side of the paper feed roller 5, there is a pair of registration rollers 6 that align the paper P sent from the paper feed roller 5 and feed the paper P at a constant speed, and a pair of registration rollers 6 that align the paper P sent from the paper feed roller 5 and send the paper P to the transfer nip of the photoreceptor drum 8. A conveyance guide roller 7 for guiding, a photosensitive drum 8 for holding an image to be transferred to paper I), and paper P
A conveyance guide roller 9 guides the paper P to the fixing roller 10, a pair of fixing rollers 10 performs heat fixing, and a paper ejection tray 1
A pair of paper ejection rollers 11 to send out the paper P to the paper P
They are provided in the order of the paper discharge trays 12 that receive the paper.

Further, near the downstream side of the fixing roller 10, a paper sensor 21 for detecting the trailing edge of the paper P is arranged. Further, a paper discharge roller controller 22 that controls the speed of the paper discharge roller 11 is provided in the drive system of the paper discharge roller 11 . This paper sensor 21 and paper ejection roller controller 22
The feature of the present invention is that the following is provided.

Next, the image forming process of the laser printer configured as described above will be explained.

First, when performing a printing operation, a signal is sent from the controller 1 to the main motor controller 2, and the main motor controller 2 drives the main motor 3. The power generated by the main motor 3 is transmitted to each roller (6 to 11) by a power transmission device 4 such as a gear. Then, when the paper feed L/ray inner paper sensor 15 detects that there is paper P in the paper feed tray 16, the controller 1 controls the paper feed clutch 13 to transfer the power from the main motor 3 to the paper feed roller. Switch so that it is transmitted to 5. The paper feed roller 5 feeds the paper P from the paper feed tray 16 toward a pair of registration rollers 6. The leading edge of the paper P is adjusted by the registration rollers 6, and then sent to the next developing section. Furthermore, in the developing section, the toner image developed on the photoreceptor drum 8 is transferred onto the paper P, which is guided by conveyance guide rollers 7.9 and sent to the fixing section. In the fixing section, the toner on the paper P is melted by a pair of heated fixing rollers 11 and is attracted to the paper P. The paper P that has been fixed (on which a printed image has been completed) is sent sequentially from the leading edge toward the ejection roller 11.
The tip of is detected. At this time, the output signal of the paper sensor 21 changes from a high level output when no paper is detected to a low level output when paper is detected, as shown at time t in FIG. The detection signal is paper sensor signal line 2
3 to the controller 1. Based on this signal, the controller 1 recognizes that the paper P is currently passing through the fixing roller 10.

After that, when the paper P is further fed, the trailing edge of the paper P is similarly detected by the paper sensor 21, and the output signal from the paper sensor 21 changes from a low level as shown at time to in FIG. 2(A). Change to a higher level. When this output signal is transmitted to the controller 1, the controller 1 recognizes that the paper P has finished passing through the fixing roller 10, sends a signal to the paper ejection roller controller 22, and sends a signal to the paper ejection roller controller 22.
Change the gear so that 1 rotates at high speed. At this time, since the leading edge of the paper P has already reached the paper discharge roller 11, the paper P after this is conveyed at high speed and sent out to the paper discharge tray 12, as shown in FIG. 2(B).

In the above embodiment, the paper sensor 21 outputs two types of signals with different levels, and sends them to the controller 1.
detects the trailing edge of the paper P, but instead, only when the signal level changes from a low level to a high level, that is, only when the trailing edge of the paper P is detected, does the paper sensor 21 detect the trailing edge of the paper P. The signal may also be sent to the paper discharge roller controller 22.

Further, as shown in FIG. 3, the paper sensor 21 may be provided immediately after the pair of registration rollers 6.

At this time, the output signal from the paper sensor 21 is similar to that explained in FIGS. 1 and 2, but as shown in FIG. This embodiment differs from the previous embodiment in that the rotation speed of the paper discharge roller 11 is not changed by the paper discharge roller controller 22 at t, ), but the rotation speed is changed after a certain period of time (a). In other words, the pair of registration rollers 6 align the leading edge of the paper P,
In order to develop the image formed on the photosensitive drum 8, which rotates at a constant speed, onto the paper P, the paper P continues to rotate at a constant speed.
is sent out. Further, the distance from the registration roller 6 to the pair of fixing rollers 10 is constant. Therefore, after a certain period of time (a) after the paper sensor 21 detects the trailing edge of the paper P (t), the trailing edge of the paper P will pass the fixing roller 10. Therefore, the controller 1 controls the time (t
, +a) sends a signal to the paper ejection roller controller 22,
As shown in FIG. 4(B), the pair of paper ejection rollers 11 are rotated at high speed to send out the paper P.

In other words, as can be easily inferred from now on, the position of the paper sensor 21 is the position where the trailing edge of the paper P passes through the pair of fixing rollers 10 after a certain period of time after the paper P is detected by the paper sensor 21. Then anywhere is fine.

Furthermore, as shown in FIG. 5, a motor different from the main motor 3 is used as the power source for the paper ejection roller 11, and the speed of the paper ejection roller 11 is controlled by the paper ejection roller controller 22 as in the previous embodiment. Instead, the rotation speed of the paper ejection roller motor 26 may be changed by the paper ejection motor controller 25 to rotate the paper ejection roller 11 at high speed.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, the actual waiting time is shortened by changing the conveyance speed of the paper from the time when the leading edge of the paper begins to be ejected until the end of the paper. This can reduce the user's discomfort in terms of sensation.

[Brief explanation of drawings]

1 to 5 show embodiments embodying the present invention. FIG. 1 is a block diagram of the first embodiment of the present invention, and FIG. 2 shows output signals of the paper sensor and paper ejection. 3 is a configuration diagram of the second embodiment of the present invention. FIG. 4 is a diagram showing the paper sensor output signal and paper discharge speed of the second embodiment.
This figure is a block diagram of a third embodiment of the present invention, and FIG. 6 is a block diagram of a conventional example. 5 Near: Paper feed roller 6: Registration roller conveyance guide roller 8: Photosensitive drum conveyance guide roller 10: Fixing roller: Paper ejection roller 21: Paper sensor: Paper ejection roller control device: Paper sensor signal line: Paper ejection roller controller 1~ Roll line: Paper ejection roller motor Driver: Paper ejection roller motor

Claims (1)

[Claims] 1. A developing device that creates an image on a sheet of paper based on data, a fixing device that fixes the image created on the sheet of paper to the sheet of paper, and a conveying device that transports the sheet of paper. The image forming apparatus includes: a detection means for detecting the position of the sheet conveyed by the conveyance means; and a conveyance speed for changing the conveyance speed of the conveyance means after the fixing means based on a detection signal from the detection means. An image forming apparatus comprising: changing means.