JPH04166853A - electronic photo printer - Google Patents

Abstract

PURPOSE:To allow a specific paper to be printed properly by changing at least one of the conditions of thermal fixing, that is the roller pressure of a thermal fixing unit and the control temperature of the heater of thermal fixing unit when it is judged that manual paper feeding is selected. CONSTITUTION:Judgement whether manual paper feeding or automatic paper feeding is selected is carried out by a paper supply judgement means M2, and when the selection of manual feeding is judged, at least one of conditions, i.e. pressure of roller of a thermal fixing unit M1 and the control temperature of a heater of the unit M1 is changed. In the case that it is judged that specific papers such as envelopes, thick paper and the like are manually fed, for example, the fixing unit M1 is drive-controlled by a thermal fixing condition control means M3 to reduce the pressure of roller or increase the control temperature of heater. It is thus possible to improve printing quality in such special papers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic printer having both manual paper feeding and automatic paper feeding.

[Prior Art] Conventionally, this type of electrophotographic printer has been provided with an automatic paper feeding mechanism that stacks a large number of sheets of normally used paper and automatically feeds the paper.

However, in these printers, which have become smaller in recent years, the paper transport path provided for automatic paper feeding is provided with a certain degree of curvature, so that special paper other than regular paper, such as envelopes and cardboard For this reason, in order to print on these special papers, in addition to the paper path for automatic paper feeding, it is difficult to automatically feed paper when using A path, for example a path with a small curvature, is provided,
By manually feeding the paper from here, the paper was fed into the printing area.

[Problems to be Solved by the Invention] However, even if such a manual feeding path is provided, when printing on special paper such as envelopes or cardboard under printing conditions for printing on normal paper that is automatically fed, It was difficult to print with good quality due to uneven printing, blurring, etc., or wrinkles on the paper.This problem is especially likely to occur when the speed of an electrophotographic printer is increased, so it is difficult to print with good quality. The present invention was made to solve the above-mentioned problems, and it is possible to suitably print on special paper such as envelopes and thick paper that are manually fed. The aim is to provide fast electrophotographic printers.

[Means for Solving the Problems] In order to achieve this object, the present invention selectively switches between manual paper feeding and automatic paper feeding from a paper storage unit, as illustrated in FIG. In an electrophotographic printer that prints using a thermal fixing device M1, a paper feed determination means M2 that determines whether the manual paper feed or automatic paper feed is selected; and the paper feed determination means M2.
If it is determined that the manual paper feeding is selected, the thermal fixing condition of at least one of the pressure of the roller of the thermal fixing device M1 or the control temperature of the heater of the thermal fixing device M1 is changed. The present invention provides an electrophotographic printer characterized in that it is equipped with a heat fixing condition control means M3.

[Function] The present invention switches between manual paper feeding and automatic paper feeding, and prints using the heat fixing device M.

Then, the paper feed determining means M2 determines whether manual paper feeding or automatic paper feeding is selected, and if it is determined that manual paper feeding is selected, the heat fixing conditions are determined. The heat fixing device M is controlled by the control means M3.
At least one of the pressure of the roller M1 and the controlled temperature of the heater of the heat fixing device M1 is changed.

For example, if it is determined that special paper such as an envelope or cardboard is being fed manually, the heat fixing condition control means M3
The heat fixing device M is driven and controlled to reduce the pressure of the roller or increase the temperature of the heater. Or control both. That is, by reducing the pressure on the rollers or increasing the temperature of the heater, the print quality on special paper is improved. Furthermore, by performing this control, it is possible to maintain a high printing speed even in the case of special paper.

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

FIG. 2 shows the external appearance of the laser printer 1 of this embodiment, and the external configuration of the laser printer 1 will be explained based on this figure.

The laser printer 1 is composed of an upper housing 2 and a lower housing 3. The tongue upper housing 2 is connected to the lower housing 3 around a hinge portion (not shown) so as to be freely openable and closable.

A paper feed cassette 4 for loading ordinary paper is removably housed inside the lower housing 3. Above the paper feed cassette 4, there is a paper feed opening 5°, a paper lower guide 6a, and a paper feed cassette 4. A manual paper feed section 7 is provided with paper lateral guides 6b and 6c. Further, above the manual paper feed section 7, a control panel 9 is provided which includes a start button 9a and the like.

A face-down tray 10 is placed on the top of the laser printer 1 to load printed paper with the print side facing down. A face-up tray 11 (Fig. 3) on which the paper is placed is arranged.

Next, the internal configuration of the laser printer will be explained using FIG.

Two paper conveyance paths are formed so as to traverse the inside of the laser printer 1: one for automatic paper feeding and one for manual paper feeding.

Among these conveyance paths, the conveyance path for automatic paper feeding runs from an automatic sheet feeding section 13 that automatically feeds paper to a registration section 14 that adjusts the image transfer timing. Process cartridge 1
5 and an image transfer unit consisting of an image transfer discharger 16]7. Image fixing device 18 which heats and fixes the image. A switching member 19 for switching the paper ejection path. The sheet is configured to reach the face-down tray]0 via the face-down paper discharge path 20, etc.

On the other hand, the conveyance path for manual paper feeding starts from the manual paper feeding section 7.
The resist portion 14. Image transfer section]7. Image fixer]8. Switching member 19. The sheet is configured to reach the face-up tray 11 via the face-up paper discharge path 21 and the like.

Each configuration will be explained in detail below.

The automatic paper feed section 13 is provided in the lower housing 3 to automatically feed paper one by one.The automatic paper feed section 13 is connected to a paper feed cassette 4. It is composed of a half-moon-shaped paper feed roller 23, feed rollers 24, 25, and the like.

On the other hand, the manual paper feed unit 7 includes a manual feed detection sensor (switch) 27 that is turned on when manual paper is inserted, and a paper feed detection sensor (switch) 27 that is turned on when manual paper is inserted, in addition to the paper feed port 5° paper lower guide 6a and paper horizontal guides 6b and 6c. It is composed of feed rollers 28, 29, etc. that convey the material into the main body of the apparatus.

The registration section 14 includes a nip section 30 where the paper is temporarily placed on standby.
．． A conveyance detection sensor 33 for detecting the conveyance state of the sheet is disposed upstream of the two rollers 31 and 32, which are composed of an upper registration roller 3], a lower registration roller 32, and the like.

The paper transport path 34 from the manual paper feed section 7 and the paper transport path 35 from the automatic paper feed section 13 are configured to merge in front of the transport detection sensor 33.

The image transfer unit 17 forms and transfers images, and is composed of a process cartridge 5 and an image transfer discharger 16, which are disposed facing each other across the paper conveyance path 37. This process cartridge 15 includes a drum-type electrophotographic photoreceptor (hereinafter referred to as drum) 38. Charger 39. Exposure section 40. The developing device 4], the cleaning device 42, and other processes are combined into a cartridge.

Furthermore, a laser scanner unit 45 is arranged above the process cartridge] 5. This laser scanner unit 45 is for performing scanning exposure on the drum 38, and is composed of a semiconductor laser 462, a rotating pot mirror (polygon mirror) 47, an fθ lens 48, a reflecting mirror 49, and the like.

The image fixing device (thermal fixing device) 18 is arranged on the downstream side of the paper conveyance path 37, and as described later, fixes the image by heating and pressurizing the paper onto which the image has been transferred. be.

The switching member 19 is provided on the downstream side of the image fixing device 18. The switching member 19 is provided on the downstream side of the image fixing device 18. Or face-up paper ejection path 2].

Here, the structure of the image fixing device 18 will be explained in detail using FIG. 4.

The image fixing device 18 includes a heating roller 52 having a built-in heater (heating element) 50, a pressure roller 53 arranged to rotate in contact with the heating roller 52, and a pressure roller 53 that conveys the paper toward the switching member 19 side. It is equipped with feed rollers 56 and 57.

A temperature sensor 60 that detects the surface temperature of the heating roller 52 and a separation claw 61 that separates the paper from the heating roller 52 are arranged on the surface of the heating roller 52.

The temperature sensor 60 is pressed against the surface of the heating roller 52 with a constant pressure by a leaf spring 62, while the separation claw 6 is rotatably supported so as to come into contact with the heating roller 52 by its own weight. .

The pressure roller 53 is supported by a lever 64 that is swingably disposed about a shaft 63, and is biased upward by a spring 65 to press the paper. Further, a solenoid 66 whose one end is fixed to the main body of the device is connected to the outer end of the lever 64, which is the point of force.

The laser printer 1 configured as described above is equipped with an electronic control device (EC) shown in FIG. 5 to control its operation.
U) 70 is provided.

This ECU 70 includes well-known RAM 70a and ROM 70.
b, CPU 70 c, input port door 0d,
It is composed of an output port door 0e, a bus line 70f connecting them, and the like.

A manual feed detection sensor 27 that detects the supply of paper from the manual paper feed section 7 and a temperature sensor 60 that detects the surface temperature of the heating roller 52 are connected to the input port door 0d. On the other hand, a solenoid 66 that pulls a lever 64 to reduce the pressure on the pressure roller 53 is connected to the output port door 0e (via a solenoid drive circuit 71). In addition to the heater 50 connected thereto, a conveyance drive motor 74 for driving each roller is connected via a conveyance drive circuit 73.

Next, the operation of the laser printer 1 of this embodiment having the above configuration will be explained based on FIGS. 3 and 4.

i) First, the case of automatic paper feeding will be explained. Normally, in response to automatic paper feeding, the voltage applied to the heater 50 is kept low, and the surface temperature of the heating roller 52 is low (for example, 1
80'C) is set. Further, the solenoid 66 is turned off, and the pressure roller 53 presses the heating roller 52 with high pressure (for example, 1 kg) by the spring 65.

First, when the start button 9a is pressed, paper is fed from the paper feed cassette 4. Here, the half-moon paper feed roller 23
As a result, the sheets in the paper feed cassette 4 are sent out toward the registration section 14 one by one with each rotation.

The paper sent out from the paper feed cassette 4 passes through the conveyance detection sensor 33, and after the leading edge is once received by the nip portion 30 of the registration rollers 31 and 32, which are stopped at that point, the paper is rotated at a predetermined timing. The driven registration rollers 31 and 32 transport the image toward the image transfer section 17 .

Image recording in this image transfer section 17 is performed as follows (2).

The drum 38 is rotationally driven in the direction of arrow C.
The entire surface is pre-exposed by a pre-exposure lamp 43 (FIG. 3) and charged by a charger 39. Next, the exposure section 4
By receiving laser scanning exposure at 0, an electrostatic latent image of a target image is formed on the surface of the drum 38.

For this laser beam scanning exposure, a laser beam is output from the semiconductor laser 46 to the polygon mirror 47 . Then, the scanning speed relative to the rotation angle of the polygon mirror 47 is converted to a substantially constant speed by the fθ lens 48, and the output direction is changed via the tongue-and-groove reflection mirror 49, thereby exposing the peripheral surface of the drum 38 to the laser beam. will be held.

The electrostatic latent image formed on the drum 38 in this manner is developed with toner by a developing device 41, and is conveyed between the drum 38 and the image transfer discharger 16.

Then, by discharging the image transfer discharge device 16, the images after toner development are sequentially transferred. Next, the paper to which the toner image has been transferred is sequentially separated from the surface of the drum 38 and introduced into the image fixing device 18 via the tag paper transport path 37.

In this image fixing device]8, as shown in FIG.
When the toner 80 is transferred to the normal paper, the toner 80 transferred to the normal paper is permanently fixed under the above-mentioned high pressure and low temperature set according to the automatic paper feeding.

Thereafter, the printed paper conveyed by the feed rollers 56 and 57 of the image fixing device 18 is guided to the face-down paper discharge path 20 by the switching member ]9, and is transferred to the face-down tray 10 at the top of the main body of the apparatus. The paper is ejected with the printed side facing down.

ii) Next, the case of manual paper feeding will be explained with reference to the flowchart in FIG.

First, when paper to be manually fed is inserted into the paper feed port 5, a switch, which is the manual feed detection sensor 27, is turned on and the insertion of the paper is detected (step 00).

Based on the signal from the manual feed detection sensor 27, the following control of the surface temperature of the heating roller 52 and the pressure of the pressure roller 53 are performed.

That is, in order to raise the surface temperature of the heating roller 52 to a high target temperature TI for manual paper feeding (for example, 190° C.), the voltage applied to the heater 50 is increased (step 110). Furthermore, in order to reduce the pressure of the pressure roller 53 to a low value (for example, 500g weight), the solenoid 6
6, thereby moving the spring 65 in the direction of arrow E (Fig. 4).
A process of pressing in the direction is performed (step 120).

Then, the temperature sensor 60 determines whether the surface temperature of the heating roller 52 has reached the target temperature T1 (Step 30), and if the temperature has reached the target temperature T1, the printing operation is started. At this time, the drive of the half-moon paper feed roller 23 is stopped so that automatic paper feeding is not performed.

When the printing operation is started, the manually inserted paper is conveyed to the registration section 4 by feed rollers 28 and 29.

Thereafter, as in the case of normal paper using automatic paper feeding, the manually fed paper passes through the conveyance detection sensor 33 and is conveyed to the image transfer unit 7 by registration rollers 31 and 32.The laser beam from the polygon mirror 47 drum 38
Exposure is performed at , and images are transferred sequentially.

Next, the transferred paper sent to the image fixing device 18 is transferred to the fourth
As shown in FIG. 1, manual paper feed 1 is
Accordingly, the toner 80 transferred to the special paper is permanently fixed by heating the card at a high temperature (target temperature TI) set in accordance with this and applying a lower pressure than the automatic paper feeding by the pressure roller 53.

Thereafter, the heat-fixed paper conveyed from the feed rollers 56 and 57 of the image fixing device 18 is sent to the face-up paper discharge path 21 by the switching member 19 and placed on the face-up tray 11.

In this way, the laser printer 1 of this embodiment uses the manual feed detection sensor 27 to detect whether or not manual paper feeding has been performed, and if manual paper feeding has been performed, the surface of the heating roller 52 This increases the temperature and reduces the pressure on the pressure roller 53.

Therefore, even if the manually fed paper is a special paper such as an envelope or cardboard, the heat fixing temperature and pressure are controlled to be appropriate, so that printing of good quality can be performed. Furthermore, since the pressure is appropriately adjusted, paper such as envelopes will not be wrinkled during heat fixing.

Furthermore, by carrying out the above-described control, even in the case of special paper, good printing can be performed without reducing the speed of thermal fixation, so that the printing speed can be increased. In other words, there is an advantage that the printing speed can be set in advance to be faster depending on automatic paper feeding.

In this embodiment, the temperature of the heating roller 52 and the pressure of the pressure roller 53 are controlled, but it is also effective to control only one of them.

Furthermore, when thermal fixing is performed at the same speed on sheets of different thicknesses as in this embodiment, the amount of heat applied to the image fixing device 18 may be changed in proportion to the increase in the thickness of the sheets. is desirable.

Further, in this embodiment, the solenoid 66 is used to change the load of the spring 65 of the image fixing device 18, but other configurations include a mechanism using a motor, an actuator using a piezoelectric element, etc. You can also use it as

[Effects of the Invention] The present invention determines whether manual paper feeding or automatic paper feeding is selected, and if manual paper feeding is selected,
Thermal fuser (This is a device that changes the fusing conditions. This allows for good quality printing even when special paper is manually fed. In addition, in the present invention, the Since the heat fixing conditions can be changed as appropriate, it is possible to quickly print on special paper without reducing printing speed.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing the present invention, Fig. 2 is a perspective view showing the laser printer of this embodiment, Fig. 3 is an explanatory diagram showing its internal structure, and Fig. 4 shows the structure of the image fixing device. An explanatory diagram, FIG. 5 is a block diagram showing the ECU, and FIG. 6 is a flowchart showing control of manual paper feeding. 1...Laser printer 18...Image fixing device (thermal fixing device) 27...Manual feed detection sensor 50...Heater 52...Heating roller 53...Pressure roller 66...Solenoid 70・Electronic control unit (ECU)

Claims (1)

[Scope of Claims] 1. An electrophotographic printer that selectively uses manual paper feeding and automatic paper feeding from a paper storage unit, and prints using a thermal fixing device, comprising: a paper feed determining means for determining whether automatic paper feeding is selected; and when the paper feeding determining means determines that the manual paper feeding is selected, the thermal fixing device is An electrophotographic printer comprising: heat fixing condition control means for changing at least one of the heat fixing conditions of the pressure of a roller and the controlled temperature of a heater of a heat fixing device.