JPH09134106A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of obtaining sufficient fixing performance even in the case of performing consecutive printing on a cardboard. SOLUTION: Whether a paper to be used is the cardboard or not, and whether the consecutive printing is performed or not are judged, the time required from the preceding transmitting of a vertical synchronizing signal VSYNC to this time transmitting of the transmitting requiring signal VSREQ of the signal VSYNC is made to be (t1) which is longer than the time (t2) for a thin paper in the case is the cardboard and the consecutive printing. Thus, the time for warming a fixing roller at temperature required for fixing can be secured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fixing control and paper conveyance control of an image recording apparatus for recording an image on recording paper based on image information from an external device.

[0002]

2. Description of the Related Art Conventionally, as an image recording apparatus of this type, there is a printer for recording an image on recording paper based on image information from an external device such as a personal computer.

Further, in such a printer, when the toner on the recording paper is thermally fixed, the temperature of the fixing roller is detected in order to secure the amount of heat required for the fixing, and the fixing device is kept to keep this temperature constant. Temperature control.

That is, the fixing roller uses a halogen heater or the like as a heat source, and controls the fixing roller to be kept at a constant temperature by turning it on and off. For example, when the paper passes through the fixing roller, the temperature of the fixing roller is lowered because heat is taken by the paper, but the heater is turned on to prevent the temperature of the fixing roller from being lowered.

Further, during continuous printing, the paper is fed on the paper path at the shortest paper interval so that the paper does not overlap in order to ensure the maximum throughput. In this case, the paper continuously takes heat from the fixing device. Therefore, the temperature of the fixing roller is kept constant by controlling the heater of the fixing device.

[0006]

However, when thick paper is continuously printed, the heat of the fixing roller is large and the temperature of the fixing roller is lowered, so that sufficient fixing property may not be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image recording apparatus which can obtain a sufficient fixing property even in continuous printing on thick paper.

[0008]

According to a first aspect of the present invention, the object is to continuously perform image recording for forming an image according to image information and recording the image on a recording material by heat fixing. The image recording apparatus which can be executed freely has a means for detecting the thickness of the recording material, and is achieved by controlling the sheet interval at the time of continuous image recording by the thickness of the recording material.

According to the second invention of the present application,
In the first aspect of the invention, the object is achieved by detecting the thickness of the recording material by the fluctuation of the distance between the two rollers in a state where the recording material is sandwiched between the two conveying rollers facing each other.

Further, according to a third invention of the present application, the object is to provide a vertical synchronizing signal of the next recording material according to the detected thickness of the recording material in the first invention or the second invention. This is achieved by controlling the timing of sending the request signal.

According to the fourth invention of the present application,
In the third aspect of the invention, the object is achieved by sending the timing of sending the request signal for sending the vertical synchronizing signal as the recording material becomes thicker.

Therefore, according to the first invention of the present application, when the thickness of the recording material is detected to be thicker than the predetermined value by the means for detecting the thickness of the recording material, the sheet interval during continuous image recording is reduced. It becomes longer than usual, and the heat taken away by the fixing operation is surely recovered, and sufficient fixing property is obtained.

Further, according to the second invention of the present application,
In the first aspect of the invention, since the thickness of the recording material is detected by the variation of the distance between the two rollers when the recording material is sandwiched between the two facing conveying rollers, the thickness of the recording material is accurately detected and the thick recording is performed. Even in the case of the material, the above-mentioned control is performed to secure the fixing property.

Further, according to the third invention of the present application, in the first invention or the second invention, the request signal of the vertical synchronizing signal of the next recording material is sent according to the detected thickness of the recording material. Since the timing is controlled, the control between the sheets is surely performed, and the fixing property is surely secured even in the case of a thick recording material.

According to a fourth aspect of the present invention,
In the third aspect of the invention, as the recording material becomes thicker, the timing of sending the request signal for sending the vertical synchronizing signal is sent, so the paper interval becomes longer and the fixability is secured.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a sectional view for explaining the configuration of an image recording apparatus showing an embodiment of the present invention, for example, a case of a laser printer.

The structure and operation will be described below. A laser printer main body 1 (hereinafter, referred to as main body 1) has a cassette 2 for accommodating a recording paper S which is a recording material, and a cassette paper for detecting the presence or absence of the recording paper S of the cassette 2 around the cassette 2. The presence / absence sensor 3, a plurality of micro switches, a cassette sensor 4 for detecting the size of the recording sheet S of the cassette 2, a sheet feeding roller 5 for feeding the recording sheet S from the cassette 2, and the like are provided.

The recording paper S is provided downstream of the paper feed roller 5.
Are provided synchronously.
An image forming unit 8 that forms a toner image on the recording paper S based on the laser beam from the laser scanner unit 7 is provided downstream of the registration roller pair 6.

Further, a fixing device 9 for thermally fixing the toner image formed on the recording paper S is provided downstream of the image forming portion 8, and the paper conveying state of the paper discharging portion is provided downstream of the fixing device 9. A discharge sensor 10 for detecting the recording sheet, a discharge roller 11 for discharging the recording sheet S, and a stacking tray 12 for stacking the recording sheet S for which recording has been completed are provided.

Further, the laser scanner section 7 has an image signal (image signal VD) sent from an external device 28 described later.
O), a laser unit 13 that emits a laser beam modulated based on O), a polygon motor 14 for scanning the laser beam from the laser unit 13 onto a photosensitive drum 17, which will be described later, an imaging lens group 15, a folding mirror 16 And the like.

The image forming section 8 includes a photosensitive drum 17, a pre-exposure lamp 18, a primary charger 19, a developing device 20, a transfer charger 21, which are required for a known electrophotographic process.
It is composed of a cleaner 22 and the like. The fixing device 9 includes a heat roller 9a, a pressure roller 9b, and a heat roller 9a.
It is composed of a halogen heater 9c provided inside and a thermistor 9d for detecting the surface temperature of the heat roller.

Further, the main motor 23 is connected to the paper feed roller 5
To the registration roller pair 6 via the registration roller 25, and each unit of the image forming unit 8 including the photosensitive drum 17, the fixing device 9, and the paper discharge. Driving force is also applied to the roller 11.

Reference numeral 26 denotes a printer control device for controlling the main body 1, which includes a timer 26a, a ROM 26b, and an R.
It is composed of an MPU (microcomputer) 26d including an AM 26c and the like, various input / output control circuits (not shown), and the like.

Further, the printer controller 26 is communicatively connected to a video controller 28 via an interface 27.

FIG. 2 shows the interface 27 shown in FIG.
It is a block diagram explaining the structure of. In Figure 2, CPR
DY is a signal indicating that the external device 28 can communicate,
It is sent from the external device 28 to the printer control device 26.

PPRDY is a signal indicating that the printer control device 26 can communicate, and is sent from the printer control device 26 to the external device 28.

SBSY is a status valid signal, which is sent from the printer controller 26 to the external device 28.

CBSY is a command valid signal, which is sent from the external device 28 to the printer control device 26.

SC is a status / command signal,
When the status valid signal SBSY is TRUE, it is sent from the printer control device 26 to the external device 28 as status data indicating the internal state of the printer, and when the command valid signal CBSY is TRUE, the external device 28 is a command indicating a command to the printer. The data is sent from the external device 28 to the printer control device 26.

CLK is a synchronous clock of the status / command signal SC and is sent from the external device 28 to the printer control device 26. For each command from the external device 28, the printer control device 26 returns one status corresponding to the command.

That is, the above SBSY, CBSY, SC, C
Handshake serial communication is performed using each signal of the LK.

RDY is a ready signal, which is set to TRUE when the printer controller 26 is in a printable state, and sent from the print controller 26 to the external device 28.

PRINT is a print signal that becomes TRUE when the external device 28 gives an instruction to start printing, and is sent from the external device 28 to the printer control device 26.

VSREQ is a vertical synchronization request signal which the printer control device 26 requests the external device 28 to output a vertical synchronization signal VSYNC which will be described later.

VSYNC is a vertical synchronizing signal for synchronizing the image output sent from the external device 28 to the printer controller 26 in the vertical direction (sub-scanning direction / paper conveying direction).

HSYNC is a horizontal synchronizing signal for synchronizing the image output sent from the printer control device 26 to the external device 28 in the horizontal direction (main scanning direction / laser scanning direction).

VDO is an image signal where the external device 28 serially sends a dot image to the printer control device 26 in synchronization with the vertical synchronizing signal VSYNC and the horizontal synchronizing signal HSYNC.

Next, FIGS. 3 and 4 show a mechanism for detecting the paper thickness by the pair of registration rollers 6 of the present invention. The resist roller pair 6 is composed of an upper resist roller 40 and a lower resist roller 41, and the upper resist roller 40 is pressed against the lower resist roller 41 by a spring 50. Since the paper passes between the upper and lower registration rollers, the upper registration roller 40 is pushed up by the thickness of the paper while the paper passes. One of the pressure sensors 42 is fixed to a fixed plate 53, and the other is fixed to a bearing 51 of the upper registration roller 40 via a rubber member 52. Therefore, when the registration roller is pushed up by the thickness of the paper while the paper passes, the pressure applied to the pressure sensor 42 increases. The thickness of the paper is detected by this pressure value. The pressure / voltage conversion unit 44 is a portion that converts the output of the pressure sensor 42 into a voltage, and the converted voltage is the A of the MPU 26d.
It is taken into the / D port. The printer operation in continuous printing of thick paper with the above configuration will be described below.

FIG. 5 shows PRINT, VSREQ, and VSYN.
6 is a timing chart showing the timings of C and VDO, the upper part is controlled so that the fastest throughput can be obtained with normal paper, and the lower part is VS when thick paper is detected.
This shows a state in which the sending of REQ is delayed and the space between sheets is opened. Let t1 be the time required for the temperature of the fixing roller to recover to the temperature required for fixing. In this way, VSRE
By delaying the delivery of Q, the temperature of the fixing roller is restored to the temperature required for fixing, and sufficient fixing property can be obtained even when printing thick paper continuously.

FIG. 6 is a flow chart of a portion for detecting VSREQ transmission timing control and paper thickness during continuous printing.

The resist roller pressure before the printing operation, that is, when the paper is not sandwiched between the resist rollers is detected, this value is stored in Pref (step S1), the thick paper flag is reset (step S2), and the printer request is issued. Wait until there is (step S3). When there is a print request, the paper is fed and the paper is carried to the registration roller (step S4), VSREQ is sent (step S9), and the thick paper flag is reset (step S10).
When the vertical synchronization signal VSYNC becomes true (step S1
1), the timer is cleared to 0 and the timer is started (step S12). This timer is V for the paper to be printed this time.
It is a timer that measures the VSREQ transmission timing of the next paper from the SYNC signal. Next, when the paper conveyance is restarted and the paper is fed (step S13), the paper enters between the upper and lower registration rollers, so that the difference between the value of the pressure sensor and the above-mentioned Pref when the paper is nipped is determined by the paper. Thickness (step S1
4) Then, it is judged by comparing with a predetermined value whether or not this corresponds to the thick paper which needs to open the space between sheets to recover the fixing temperature (step S15), and if it is the thick paper, the thick paper flag is set. (Step S16).

Further, it is confirmed whether or not the continuous printing is performed (step S17). If the PRINT signal is true for continuous printing, the next paper is fed and fed to the front of the registration roller (step S5). Whether or not the paper is thick paper is confirmed by the thick paper flag (step S6). If it is thick paper, check the time from the previous VSYNC with a timer (step S7), and when the time t1 has elapsed, VSREQ
The signal is made true (step S9). When the paper is not thick paper, the VSREQ signal is set to true every t2 hours (steps S8 to S9).

By the control as described above, in the case of thick paper, it is possible to secure the time for warming the fixing roller at the temperature required for fixing.

(Second Embodiment) FIGS. 7 and 8 show a second embodiment of the present invention, in which a micro displacement sensor is used as a mechanism for measuring the thickness of paper by a resist roller.

The micro-displacement sensor 60 is a type of sensor in which light emitted from an LED is applied to a measurement object, reflected light is detected by a plurality of sensors, and the distance to the measurement object is detected based on the difference.

When the paper enters between the upper and lower registration rollers 40 and 41, the upper registration roller 40 is pushed up and the distance between the bearing 51 and the displacement sensor 60 changes. This is detected to measure the thickness of the paper.

Since other operations are the same as those in the first embodiment, the description thereof will be omitted.

[0049]

As described above, the first embodiment according to the present application is described.
According to the invention of, having means for detecting the thickness of the recording material,
Since the paper interval during continuous printing is controlled by the thickness of the recording material,
It is possible to recover the temperature of the fixing roller, which has been lowered due to the fixing of the previous recording material, and to secure sufficient fixing performance even in continuous printing of thick recording material.

According to the second aspect of the present invention,
In the first aspect of the invention, since the thickness of the recording material is detected by the change in the distance between the two rollers in the state where the recording material is sandwiched between the two opposing transport rollers, the thickness of the recording material can be reliably detected to be thick. Sufficient fixing performance can be secured even for continuous printing of recording materials.

Further, according to the third invention of the present application, in the first invention or the second invention, the request signal of the vertical synchronizing signal of the next recording material is transmitted according to the detected thickness of the recording material. Since the timing is controlled, it is possible to reliably control the sheet interval, and it is possible to sufficiently secure the fixability in continuous printing of a thick recording material.

According to the fourth aspect of the present invention,
In the third aspect of the invention, as the recording material becomes thicker, the transmission timing of the request signal of the vertical synchronizing signal is sent, so that the thicker the recording material, the longer the paper interval,
The fixability can be sufficiently secured.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus according to a first embodiment of the present invention.

FIG. 2 is an interface between an external device and a printer according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of a paper thickness detection unit according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of a paper thickness detection unit according to the first embodiment of the present invention.

FIG. 5 is a timing chart in the first embodiment of the present invention.

FIG. 6 is a flowchart in the first embodiment of the present invention.

FIG. 7 is a configuration diagram of a paper thickness detection unit according to the second embodiment of the present invention.

FIG. 8 is a configuration diagram of a paper thickness detection unit according to the second embodiment of the present invention.

[Explanation of symbols]

1 Laser Printer (Image Recording Device) 40 Upper Registration Roller (Means for Detecting Thickness of Recording Material) 41 Lower Registration Roller (Means for Detecting Thickness of Recording Material) 42 Pressure Sensor (Means for Detecting Thickness of Recording Material) 60 Displacement sensor (means for detecting the thickness of recording material) S recording paper (recording material) VSYNC vertical synchronization signal VSREQ vertical synchronization signal transmission request signal

Claims (4)

[Claims] 1. An image recording apparatus capable of continuously performing image recording for forming an image according to image information and recording the image on a recording material by heat fixing, and having a means for detecting the thickness of the recording material. An image recording apparatus characterized in that the distance between sheets during continuous image recording is controlled by the thickness of the recording material. 2. The image recording apparatus according to claim 1, wherein the thickness of the recording material is detected by a change in the distance between the two rollers when the recording material is sandwiched between two facing conveying rollers. 3. The image recording apparatus according to claim 1 or 2, wherein the transmission timing of a request signal of a vertical synchronizing signal of the next recording material is controlled by the detected thickness of the recording material. 4. The image recording apparatus according to claim 3, wherein the transmission timing of the vertical synchronizing signal transmission request signal is sent as the recording material becomes thicker.