JP2000347536A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image forming device constituted so that a fixed image whose light transitivity and color developing property are sufficiently secured even when a recording body having a characteristic being different from an assumed standard fixing characteristic is used is obtained. SOLUTION: When a fixing test image T is formed on an OHP sheet S (S1), the standard intensity Ibr of the straight-advance transmitted light of the image T is calculated based on the surface temperature (fixing temperature) of a heating roller 2 detected by a temperature sensor at a step S2 and test image data obtained at a step S3 by a general control part (S4). On the other hand, the intensity Ib of the straight-advance transmitted light of the image T is detected by a transmitted light intensity information detection part (S5). Next, the fixing characteristic of the sheet S is estimated by comparing the intensity Ibr obtained at the step S4 and the intensity Ib obtained at the step S5 by the general control part (S6). Besides, fixing conditions are corrected so that a proper heating value can be supplied based on the estimated result by the control part (S7).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus such as a copying machine and a printer. More specifically, the present invention relates to an image forming apparatus capable of always obtaining a fixed image with sufficient translucency and color development even when a recording medium having characteristics different from assumed fixing characteristics is used. Things.

[0002]

2. Description of the Related Art For example, in an image forming apparatus such as an electrophotographic copying machine, a permanent image is obtained by fixing a toner image transferred to a recording medium. Here, as a fixing method, there are methods such as heat fixing, pressure fixing, and solvent fixing. Among them, a contact heating type fixing device using heat fixing is widely and generally used. As this fixing device, for example, a fixing device including a heating roller and a pressure roller is known. The heating roller is a metal roller having good heat conduction and small heat capacity. The heating roller has a heater lamp inside, and the surface temperature is detected by a thermistor or the like, and the temperature is controlled so as to be within a predetermined fixing temperature range. On the other hand, the pressing roller has a core material whose surface is coated with elastic silicon rubber or the like. The heating roller and the pressure roller are rotatably supported in a state where they are pressed against each other. When the recording material on which the toner image is transferred passes between the heating roller and the pressure roller, the toner melts. At the same time, the toner image is pressed against the recording medium to fix the toner image, thereby obtaining a permanent image. In some cases, a heater lamp is provided inside the pressure roller.

Here, OH having a large heat capacity is used as a recording medium.
If a P-sheet or thick paper is used and fixing is performed under the same conditions as plain paper, the toner may not be sufficiently melted, resulting in poor fixing. For this reason, by increasing the fixing temperature or decreasing the fixing speed, a larger amount of heat is supplied than is supplied to plain paper, so that good fixability is ensured.

[0004]

However, in the conventional apparatus, it was not possible to detect the quality of the image of the fixed image fixed on the recording medium. The quality of the image condition was not understood. Therefore, for example, when an OHP sheet different from what is assumed as a standard fixing characteristic (for example, a sheet having a different ease of fixing depending on a difference in thickness and a maker, whether or not it is dedicated to a color, or the like) is used. However, there is a possibility that the fixing device cannot supply an appropriate amount of heat to the OHP sheet or the like, so that a good image state cannot be secured.
Further, it is difficult to judge the quality of the image fixed on the OHP sheet only by visual inspection, and the quality of the image is not determined until the actual translucent image is visually recognized by the projector. For this reason, if the image state is poor and sufficient translucency and coloring properties are not ensured, much time must be spent to make a copy again, or an unsatisfactory OHP sheet must be used. Had to be done.

Accordingly, the present invention has been made to solve the above-mentioned problems, and has a sufficient light transmitting property even when a recording medium having characteristics different from the assumed standard fixing characteristics is used. It is an object of the present invention to provide an image forming apparatus capable of obtaining a fixed image ensuring the properties and coloring properties.

[0006]

According to an image forming apparatus according to the present invention, which has been made to solve the above-mentioned problems, an image forming means for forming an unfixed image on a recording medium, and an image forming apparatus comprising: In an image forming apparatus having a contact heating fixing unit for fixing a created unfixed image on the recording medium by contact heating, a fixing temperature detecting unit for detecting a fixing temperature in the contact heating fixing unit, and the contact fixing unit A light-emitting element for irradiating light to a fixed image fixed on the recording medium, and a light-receiving element for detecting intensity information of transmitted light emitted from the light-emitting element and transmitted through the recording medium and the fixed image. Intensity information detecting means, image data corresponding to the unfixed image created by the image creating means, the fixing temperature detected by the fixing temperature detecting means, and the transmitted light intensity information detecting means. A characteristic estimating unit for estimating the fixing characteristic of the recording medium based on the detection result of the recording medium, a fixing condition correcting unit for correcting the fixing condition in the contact heating fixing unit based on the estimation result of the characteristic estimating unit, Having.

In this image forming apparatus, first, an image forming means forms an unfixed image (toner image) on a recording medium. Here, the unfixed image created on the recording medium by the image creating means includes not only a copy image of a document to be copied, image data input to the image forming apparatus, but also pre-stored in the image forming apparatus. A predetermined test image based on the test image data is also included. Next, the contact heating fixing unit fixes the unfixed image created by the image creating unit on the recording medium. At this time, the fixing temperature detecting means detects the fixing temperature in the contact heating fixing means. When the fixing is completed, the transmitted light intensity information detecting means detects the transmitted light intensity information of the fixed image fixed on the recording medium.

The intensity information of the transmitted light is detected by irradiating the fixed image on the recording medium with light by the light emitting element and receiving the transmitted light transmitted through the recording medium and the fixed image by the light receiving element.
Irradiation of light from the light emitting element to the fixed image is performed directly or via a recording medium. The light received by the light receiving element is transmitted light that has passed through both the recording medium and the fixed image. Note that any light emitting element may be used as long as it emits light in the visible light region. For example, a halogen lamp, a light emitting diode, a semiconductor laser, and the like can be given. Further, the light receiving element may be any element having a sensitivity range that responds to light emitted from the light emitting element. For example, a CCD, a photodiode, and the like can be given.

Then, the characteristic estimating means records based on the image data corresponding to the unfixed image created by the image creating means and the fixing temperature detected by the fixing temperature detecting means, and has a recording having the assumed standard fixing characteristic. The intensity of the transmitted light of the fixed image when fixed to the body (hereinafter, this intensity is referred to as the “standard intensity”).
Is calculated. Next, the characteristic estimating unit estimates the fixing characteristic of the recording medium by comparing the standard intensity with the detection result of the transmitted light intensity information detecting unit. afterwards,
The fixing condition correcting means corrects the fixing condition in the contact heating fixing means according to the fixing characteristics of the recording medium estimated by the characteristic estimating means.

[0010] Thereby, how much the fixing characteristics of the used recording medium are superior (easy to fix) or inferior to the assumed fixing characteristics (standard fixing characteristics). (It is difficult to fix). For this reason, the correction amount of the correction performed by the correction unit becomes clear, and the fixing condition can be appropriately corrected. Therefore, since an appropriate amount of heat according to the fixing characteristics of the recording medium is supplied to the recording medium, even when a recording medium having characteristics different from the assumed fixing characteristics is used, sufficient translucency and coloring properties are obtained. Can be obtained.

The reason why the fixing characteristics of the recording medium can be estimated based on the intensity information of the transmitted light of the fixed image is that there is a correlation between the transmittance of the fixed image and the fixing characteristics. For example, under the same fixing conditions, when the toner is not sufficiently fixed (when it is difficult to fix), the transmittance of the fixed image decreases. On the other hand, when the toner is sufficiently fixed (when it is easy to fix), light passes through the fixed image without being refracted, so that the transmittance of the fixed image increases.

Referring to the drawings, if it is easy to fix the toner, the toner melts sufficiently and the surface of the fixed image TGA on the recording medium S becomes smooth as shown in FIG. The intensity of transmitted light increases. In this case, when projected by the projector, the image looks bright and has a good image.
On the other hand, when it is difficult to fix the toner, the toner is not sufficiently melted as shown in FIG. Since the light is refracted and transmitted, the intensity of the refracted transmitted light increases and the intensity of the straight transmitted light decreases. In this case, when the image is projected by the projector, the image looks slightly black and is poor.

Therefore, by detecting the intensity information of the straight transmitted light or the refracted transmitted light, it is possible to estimate the fixing characteristics of the recording medium. Note that the straight transmitted light refers to the transmitted light in which the incident light that has entered the fixed image travels straight without being bent by refraction or the like (in the following description, “straight transmitted light” is used in the same meaning). The term “refracted transmitted light” refers to transmitted light whose incident light that has entered a fixed image has its path deflected due to refraction or the like (in the following description, “refracted transmitted light” is used in the same sense).

In order to obtain the transmittance, the intensity of incident light is required in addition to the intensity of transmitted light. Therefore, in addition to the transmitted light,
The intensity of the incident light may be separately detected. However, when the intensity of the incident light is known, such as when the intensity is constant, the evaluation can be performed only with the intensity of the transmitted light. In addition, in the measurement of the intensity of the incident light, a method of directly measuring the intensity using a half mirror or the like, and a method of indirectly measuring the applied voltage, the current consumption, the power consumption, and the like of the light emitting element can also be used. .

Here, in detecting the transmitted light intensity information, it is desirable to obtain the intensity information of the straight transmitted light. The transmittance of the straight transmitted light, or the intensity information of the straight transmitted light, for example,
Since the transmittance can range from 0% to 100% and the intensity information can range from zero to almost the same value as the intensity of the incident light, refracted transmitted light is detected at a point where the measurement range is wide and strong against noise. This is because it is more advantageous than the case where In addition,
Compared to the case of using only the intensity information of the linearly transmitted light, the information of the incident light intensity (luminous intensity) of the light emitting element is also obtained, and the linear transmissivity (the ratio of both) is calculated and used. This is more desirable because it also becomes strong against disturbances such as fluctuations in light emission intensity.

Further, instead of obtaining the intensity information of the straight transmitted light in detecting the transmitted light intensity information, the intensity information of the refracted transmitted light may be obtained. The transmittance of the refracted transmitted light, or the intensity information of the refracted transmitted light, is smaller in the value of the transmissivity and the intensity information obtained in comparison with the straight transmitted light, and its range, that is, the measurement range is narrow, but it is larger depending on the quality of the image state. Since the value changes, it is more advantageous than the case of using straight transmitted light in that the fixing characteristics of the recording medium can be easily estimated. In addition, as compared with the case where only the intensity information of the refraction and transmission light is used, the incident light intensity information of the light emitting element is also obtained and the refraction transmittance is calculated and used. ) Is more preferable because it also becomes strong against disturbances such as fluctuations in (1).

Further, in the detection of transmitted light intensity information, intensity information of both straight transmitted light and refracted transmitted light may be obtained. As described above, by obtaining the intensity information of both the straight transmitted light and the refracted transmitted light, it is possible to reduce the influence of disturbance or noise due to the fluctuation of the light emission intensity of the light emitting element even without obtaining the incident light intensity information. Because.

Further, in the image forming apparatus according to the present invention, the fixing condition correcting means includes at least one of a fixing temperature, a fixing speed, and a fixing pressure in the contact heating fixing means based on an estimation result by the characteristic estimating means. Correct one.

As described above, the fixing condition correcting means changes at least one of the fixing temperature, the fixing speed, and the contact pressure in the contact heating fixing means based on the result of estimation by the characteristic estimating means, so that the contact heating fixing is performed. The means can supply an appropriate amount of heat to the recording medium according to the fixing characteristics of the recording medium. Thus, even when a recording medium having characteristics different from the assumed fixing characteristics is used, it is possible to obtain a fixed image with sufficient translucency and color development.

The correction target in the fixing condition correction means is:
Any one of the fixing temperature, the fixing speed, and the contact pressure in the contact heating fixing unit may be used, or two or three conditions may be corrected simultaneously. By simultaneously correcting two or three conditions, it is possible to increase the range of change in the amount of heat supplied to the recording medium that can be dealt with by the correction. For example, even if only one condition is corrected, the amount of heat supplied becomes insufficient. It is effective in the case. Further, contradictory conditions may be corrected, for example, by increasing the fixing speed while increasing the fixing temperature. In this case, the amount of heat supplied to the recording medium can be more finely controlled.

Further, in the image forming apparatus according to the present invention, the image forming means has a test image data memory for storing test image data for forming a predetermined test image on the recording medium, and Preferably, the light intensity information detecting means detects intensity information of transmitted light of the fixing test image fixed on the recording medium.

Since the position of the fixed image to be detected is known in advance by using the fixing test image obtained from the previously stored test image data, the intensity information of the transmitted light of the fixed image is surely obtained. Can be obtained. For this reason, the characteristic estimating means can reliably estimate the fixing characteristic of the recording medium. Along with this, the correction means,
Since the fixing conditions can be appropriately corrected, an appropriate amount of heat according to the fixing characteristics of the recording medium is supplied to the recording medium from the contact heating fixing unit. As a result, even when recording media having different fixing characteristics are used, it is possible to obtain a fixed image in which sufficient light-transmitting properties and coloring properties are secured.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of an image reading apparatus according to the present invention will be described in detail with reference to the drawings. First, the first embodiment will be described. A first embodiment is an electrophotographic copying machine equipped with an image forming apparatus according to the present invention,
A predetermined fixing test image is created on the OHP sheet to be used, the fixing characteristics of the OHP sheet are estimated based on the transmitted light intensity information of the fixing test image, and the fixing temperature among the fixing conditions is determined based on the estimation result. It is to be corrected.

As shown in FIG. 1, the copying machine 1 includes an image reader section IR and a page printer section PRT. Then, based on the image data transferred from the image reader section IR, the page printer section PRT prints the image of the document by an electrophotographic process.

The image reader section IR includes an original glass 10
An image reading unit 2 that detects reflected light from an image of a document set thereon, photoelectrically converts the reflected light, and reads image data corresponding to the image of the document, and an image that performs data processing according to various image forming modes. And a processing unit 3. Note that the image reading section 2 includes a data memory section 9 for temporarily storing the read image data. A document cover 11 for holding a document is mounted above the image reader IR.

On the other hand, the page printer section PRT has an optical scanning section 4, an image processing section 5, and a transport section 6.
The optical scanning section 4 includes a polygon mirror 21 and a reflection mirror 22 for scanning and irradiating the photosensitive drum 30 with laser light. The image processing unit 5 includes a photosensitive drum 30, a charging charger 31, and developing units 32Y and 3
2C, 32M, 32K, a transfer drum 34 having a transfer charger 33, and a cleaning device 35. The transport unit 6 includes a paper cassette 44 for stacking and storing the recording medium.
And various transport rollers for transporting the recording medium supplied from the paper cassette 44 or the manual feed tray 45; a fixing device 40; a transmitted light intensity information detecting unit 43 including a halogen lamp 41 and a CCD sensor 42; And a discharge tray 46 for accommodating the recording medium discharged outside the apparatus after the completion of the operation.

Here, the fixing device 40 is composed of a heating roller 212 and a pressure roller 213 which are arranged vertically, and the details will be described with reference to FIG. FIG. 2 shows a cross section of the fixing device 40 in the longitudinal direction. As shown in FIG. 2, the heating roller 212
Silicon rubber 212 is provided on the surface of a metal cylinder 212a made of a material such as aluminum having good heat conduction and small heat capacity.
b. A heater lamp 221 is provided inside the heating roller 212, and is supplied with power and heated based on temperature control by a general control unit 54 (see FIG. 5) described later. The surface temperature of the heating roller 212 is detected by a temperature sensor 222 such as a thermistor provided in contact with the surface. The surface temperature signal detected here is
It is input to the overall control unit 54 described later. On the other hand, similarly to the heating roller 212, the pressing roller 213 has a silicon cylinder 21a in a metal cylinder 213a having a heater lamp 221 therein.
3b.

When the pressure roller 213 is driven by a drive control unit 55 (see FIG. 5), which will be described later, the heating roller 212 also rotates following the pressure roller 213. Note that, instead of the pressing roller 213, the heating roller 212 may be driven by the drive control unit 55, and the pressing roller 213 may be rotated by following the heating roller 212.

The transmitted light intensity information detecting section 43 is for grasping information for detecting the image state of the fixed image, and more specifically, for detecting the transmitted light intensity information of the fixed image. It is. This transmitted light intensity information detection unit 43
For example, as shown in FIG. 3, when the fixing test image T having a substantially rectangular shape is formed on the OHP sheet S at the upper left corner when the transport direction indicated by the arrow in the OHP sheet S is turned upward. It is arranged at a position where the intensity of the transmitted light of the fixing test image T can be measured. That is, in the OHP sheet S, behind the fixing device 40, a halogen lamp 41 as a light emitting element is provided below the OHP sheet S discharged from the fixing device 40 in the figure, and the optical axis 41L of the halogen lamp 41 is provided. A CCD sensor 42, which is a light receiving element, is provided on the upper side in the figure so as to sandwich the conveyance path of the OHP sheet S on the same axis as the above. As described above, the transmitted light intensity information detecting unit 43 is configured in a state where the halogen lamp 41 and the CCD sensor 42 form a pair.

The arrangement of the halogen lamp 41 and the CCD sensor 42 may be reversed. In addition to the case where the optical axis 41L of the halogen lamp 41 is orthogonal to the OHP sheet S as shown in FIG. 3, the optical axis 41L of the halogen lamp 41 and the OHP sheet S form a predetermined angle as shown in FIG. The halogen lamp 41 and the CCD sensor 42
May be arranged.

However, when the halogen lamp 41 and the CCD sensor 42 are arranged as shown in FIG.
It is desirable that the angle between L and the recording medium is 45 degrees or more. If the angle is smaller than 45 degrees, the component of the reflected light becomes large, and the intensity information of the straight transmitted light cannot be measured accurately. Further, the angle is more preferably 90 degrees (the state of FIG. 3). Thus, the halogen lamp 41
If the CCD sensor 42 is arranged, the influence of the thickness of the fixing test image T and the lifting of the recording medium S during measurement can be made less likely, and the intensity information of the straight transmitted light can be measured more accurately.

By arranging the halogen lamp 41 and the CCD sensor 42 in this manner, the transmitted light intensity information detecting section 43 can detect the intensity information of the straight transmitted light of the fixing test image T. That is, the transmitted light intensity information detection unit 4
No. 3 detects the intensity information of the straight transmitted light of the fixing test image T by detecting the intensity Ib of the transmitted light received by the CCD sensor 42. The intensity information of the straight transmitted light is detected because it has a positive correlation with the quality of the fixing property of the recording medium as described above, and has a wide measurement range and is strong against noise. Further, the image information detecting section 43
In the above, the emission intensity Ia of the halogen lamp 41 may also be detected to detect the ratio between the two (that is, transmittance = Ib / Ia). Thereby, the halogen lamp 4
This is because it is possible to eliminate the influence on the intensity Ib of the transmitted light due to the fluctuation of the light emission intensity Ia. In the present embodiment, the light emission intensity of the halogen lamp 41 is kept constant, and the transmitted light intensity information is used as it is without obtaining the transmittance.

Here, the OHP sheet S is obtained by coating a base layer formed of polyethylene terephthalate (PET) with a coat layer of a polyethylene resin or the like, and further coating an electric resistance control layer on the coat layer. is there. And O
The fixing characteristics of the HP sheet change depending on the thickness and melting characteristics (viscosity, molecular weight, etc.) of the coat layer. For this reason, OHP
By obtaining the intensity information of the transmitted light of the fixed image fixed on the sheet, the melting state of the toner and the coat layer can be known, so that the fixing characteristics of the OHP sheet can be estimated.

Next, the operation of the copying machine 1 configured as described above when copying an OHP sheet will be briefly described with reference to FIG. In the copying machine 1, the following processing is performed in the order of yellow (Y), cyan (C), magenta (M), and black (K) reproduction colors. First,
The processing of yellow (Y) will be described. Image reading unit 2
Reads image data corresponding to yellow (Y) in the image of the document. In addition, the surface of the photosensitive drum 30 rotating in the direction of the arrow in FIG. 1 is uniformly charged by the charging charger 31. Then, a laser control unit 5 to be described later
9 (see FIG. 5), the image data read by the image reading unit 2 is input. Then, the laser light is modulated and emitted from the laser light source, and this laser light is scanned in the main scanning direction by the polygon mirror 21, further reflected by the reflection mirror 22, and enters the photosensitive drum 30. As a result, an electrostatic latent image corresponding to the reproduced color of yellow (Y) is formed on the photosensitive drum 30. This electrostatic latent image is
The toner image is developed by the developing device 32Y. This toner image is transferred onto the OHP sheet S supplied from the paper cassette 44 or the manual feed tray 45 by the transfer charger 33 arranged opposite to the photosensitive drum 30.

Next, cyan (C), magenta (M),
The processing for black (K) is performed similarly. By these processes, the four color toner images are transferred onto the OHP sheet S in a superimposed manner. Thereafter, the OHP sheet S to which the toner image has been transferred is heated and pressed in the fixing device 40. As a result, the toner is melted, and the toner image is fixed on the OHP sheet S to form a full-color image. After the image is fixed, the OHP sheet S is discharged out of the apparatus and stored in the paper discharge tray 46. This completes the copying for one sheet.

Here, a control system of the copying machine 1 for controlling such a copying operation and the like will be described. As shown in the block diagram of FIG.
4 as the center. The general control unit 54 corresponds to the characteristic estimating unit and the fixing correcting unit of the present invention, and is a microcomputer configured by combining a known CPU, a ROM, a RAM, and the like. Overall control unit 54
Various programs necessary for executing the control of the copying machine 1, reference data, and the like are prepared and stored in the ROM incorporated in the CPU. Note that test image data for creating a test image described later is
It is stored in the OM. In addition, the RAM temporarily stores numerical values and the like that appear during execution of the arithmetic processing,
Various buffers are provided for reading data as needed.

An input / output port of the general control unit 54 includes an IR control unit 51 for controlling the operation of the image reading unit 2 and a fixing unit 4.
Drive control unit 5 that performs drive / stop of 0 and rotation speed control
5, a transport control unit 56 for controlling the supply of a recording medium such as an OHP sheet, a scanner control unit 57 for controlling the scanning of the laser beam by the polygon mirror 21, and a control for charging the photosensitive drum 30, developing bias and transfer bias. A high-voltage control unit 58 that controls a high voltage such as application, a laser control unit 59 that performs modulation control of laser light, a transmitted light intensity information detection unit 43,
A temperature sensor 222 that detects the fixing temperature of the fixing device 40 (more precisely, the surface temperature of the heating roller 212), a heater lamp 221 and the like are connected. In addition, the general control unit 5
Signals from an operation panel 53 are input to the controller 4 via a controller 52.

The copier 1 is controlled by the general control unit 54 and operates as follows. First, OH
Control information such as the size and type of the P sheet is input from the operation panel 53 to the controller 52. Next, when the copy button on the operation panel 53 is pressed, a copy request signal is transmitted, and this signal is received by the controller 52. Then, a print command is output from the controller 52 to the overall control unit 54. In response to this command, the general control unit 54 instructs the IR control unit 51 to start reading an image of a document, and instructs the transport control unit 56 to start supplying an OHP sheet. Scan preparation is instructed.
Also, a command is output to the high-voltage control unit 58, and the charging of the photosensitive drum 30, the developing bias, and the transfer bias are set, and preparation for image formation is performed. When the reading of the image of the original by the image reading unit 2 is completed, the read image data is input to the laser control unit 59.

Next, the overall control unit 54 controls the controller 5
2 to output a vertical synchronization request signal and wait for reception of a vertical synchronization signal. Then, when the controller 52 outputs the vertical synchronization signal, the laser light is modulated and emitted based on the image data input to the laser control unit 59. As a result, an electrostatic latent image is formed on the photosensitive drum 30 and the developing device 32Y
(32C, 32M, 32K) to form a toner image. This toner image is transferred to an OHP sheet and fixed by the fixing device 40 to form a fixed image. At this time, the temperature sensor 222 detects the surface temperature (fixing temperature) of the heating roller 212 of the fixing device 40 and transmits the detection result to the overall control unit 54.

Here, the operation of the copying machine 1 when creating the fixing test image T will be described with reference to the flowchart shown in FIG. The subroutine shown in this flowchart is performed after a predetermined number of copies have been made, after a predetermined operation time has elapsed, or when the operator
This is performed when the test mode is selected from the menu. First, test image data stored in advance in the ROM in the integrated control unit 54 is input to the laser control unit 59 shown in FIG. 5, and a predetermined fixing test image T is created by the above procedure (S1). .

It is preferable that the fixing test image T be a patch other than black (K), and yellow (Y), cyan (C), and magenta (M) using one type of toner.
Or a patch of an arbitrary color using a plurality of toners. When a plurality of toners are used, the melting state of the toner in various images can be detected. Further, since the amount of toner adhered to the fixing test image T can be increased, the result can be used to widen the amount of toner adhered and other correction ranges. Further, a plurality (three or more) of fixing test images having different image densities by a predetermined value may be created in the recording medium transport direction. In this way, the transmitted light intensity (transmittance) of each fixing test image is detected, and a straight line representing the relationship between the image density and the transmitted light intensity (transmittance) is obtained from the result by the least square method, A true value of transmitted light intensity (transmittance) for each fixing test image can be obtained. With this, compared to creating only one fixing test image,
The transmitted light intensity (transmittance) of the fixing test image can be detected with higher accuracy. Therefore, the image state of the fixing test image can be grasped more accurately. Alternatively, a plurality (three or more) of fixing test images having the same image density may be created in the recording medium transport direction, and the average value of the transmitted light intensity (transmittance) of each fixing test image may be obtained.

The surface temperature of the heating roller 112 when the OHP sheet S passes through the fixing device 40, that is, the fixing temperature is detected by the temperature sensor 222 (S2). continue,
The overall control unit 54 calls and reads the test image data stored in the ROM (S3), and reads the read test image data and the surface temperature (fixing temperature) of the heating roller 212 detected by the temperature sensor 222. The standard intensity Ibr of the straight transmitted light of the fixing test image T when the fixing test image T is fixed on the OHP sheet having the assumed standard fixing characteristics is calculated based on
4).

On the other hand, the transmitted light intensity information detecting section 43
The intensity Ib of the straight transmitted light of the fixing test image T created on the P sheet S is measured, and this data is transmitted to the general control unit 54.
(S5). Then, the overall control unit 54 estimates the fixing characteristics of the OHP sheet S by comparing the intensity Ib of the straight transmitted light with the standard intensity Ibr of the straight transmitted light calculated in S4 (S6). This estimation is performed in a seven-step evaluation (A to G ranks) as shown in Table 1. In other words, the fixing characteristics assumed in the copying machine 1 are set as the standard (D rank), and the evaluation is performed by being classified into three levels for the side where the fixing is easy and the side where the fixing is difficult.

[0044]

[Table 1]

By comparing the standard intensity Ibr with the actually measured intensity Ib, it can be seen how the fixing property of the used recording medium is superior to the recording medium having the assumed standard fixing property. (Easy to fix)
Alternatively, it is possible to know how inferior (it is difficult to fix). Therefore, as described later, the correction amount of the control temperature of the heater lamp 221 becomes clear, and the fixing temperature can be appropriately corrected.

Thereafter, the overall control unit 54 corrects the fixing temperature in the fixing unit 40 based on the estimation result (A to G ranks) (S7). Specifically, the general control unit 54
Changes the control temperature of the heater lamp 221 as shown in Table 1. For example, when the general control unit 54 estimates that the fixing property of the OHP sheet S is F rank, the control temperature of the heater lamp 221 is changed from 160 ° C. (standard set temperature) to 10 degrees.
% To 176 ° C.

By such correction, an appropriate amount of heat is supplied according to the fixing characteristics of the OHP sheet S, and the fixing is performed. Therefore, it is possible to obtain a fixed image in which sufficient translucency and coloring properties are secured. Therefore, it is possible to avoid unnecessary copying of the copy and use of an OHP sheet having a poor appearance.

As described above in detail, according to the copying machine 1 of the first embodiment, a predetermined fixing test image T is created on the OHP sheet S periodically or by an operator's selection. Then, the transmitted light intensity information detecting section 43 measures the intensity Ib of the straight transmitted light of the fixing test image T. Then, the overall control unit 54 determines the intensity Ib of the straight transmitted light detected by the transmitted light intensity information detection unit 43, the test image data, and the heating roller 212 detected by the temperature sensor 222.
The fixing characteristic of the OHP sheet S is estimated by comparing with the standard intensity Ibr of the straight transmitted light of the fixing test image T calculated based on the surface temperature (fixing temperature). Thereafter, based on this estimation result, the overall control unit 54
The fixing temperature in the fixing device 40 is corrected so that an appropriate amount of heat according to the fixing characteristics of the sheet S can be supplied. As a result, even when the OHP sheet S has characteristics different from the standard fixing characteristics of the copying machine 1, an appropriate amount of heat is supplied according to the fixing characteristics to perform fixing. Therefore, it is possible to obtain a fixed image in which sufficient translucency and coloring properties are secured.

In the first embodiment, the OHP
Although one patch-shaped fixing test image (hereinafter, also simply referred to as “patch”) T is created on the sheet S, the fixing test image is created in the transport direction of the OHP sheet S as shown in FIG. A pattern formed by arranging a plurality of patches TP in a direction (horizontal direction in the drawing) orthogonal to the upper direction), and as shown in FIG.
A pattern created by arranging the sheet S in the conveying direction (vertical direction in the drawing), a pattern creating patches TP at four corners of the OHP sheet S as shown in FIG. 7, and an OHP as shown in FIG.
A pattern in which a plurality of patches TP are arranged on a diagonal line of the sheet S and the like are exemplified.

Here, in the case where the transmitted light intensity information detecting section 43 composed of one set of the halogen lamp 41 and the CCD sensor 42 is used as exemplified in the first embodiment, FIG. With the pattern shown, the intensity information of the transmitted light can be detected for a plurality of patches TP. On the other hand, when patterns such as those shown in FIGS. 5, 7, and 8 are created as fixing test images, transmitted light intensity information detection including a plurality of sets of halogen lamps and a CCD sensor in a direction intersecting the transport direction is performed. Department. In any case, when the transmitted light intensity information of the plurality of fixing test images (patches) TP is detected, the transmitted light intensity information can be accurately measured by calculating an average value or the like. As a result, the fixing characteristics of the OHP sheet are more accurately estimated, so that the fixing temperature can be more appropriately corrected.

Further, in addition to creating only a fixing test image on the OHP sheet S as in the above-described embodiment, a fixing test image TP is superimposed on an actual copy image GA as shown by a broken line in each figure by an operator's selection. You may make it. When the fixing test image TP is superimposed on the copy image GA, an image forming the fixing test image TP on the periphery of the OHP sheet as shown in FIGS.
This is because in the pattern as shown in FIG. 8, the copy image GA and the fixing test image TP overlap.

(Second Embodiment) Next, a second embodiment will be described. The copying machine according to the second embodiment has substantially the same configuration as that of the copying machine 1 according to the first embodiment, but the fixing temperature in the fixing device is determined based on the fixing characteristics of the OHP sheet used. Instead of changing
The difference is that the fixing speed is changed. That is, the overall control unit 54 issues an instruction to the drive control unit 55 to
The second rotation speed is changed. Therefore, control for correcting the fixing speed will be described with reference to a flowchart shown in FIG. The subroutine shown in this flowchart is performed after a predetermined number of copies have been made, after a predetermined operation time has elapsed, or when the operator has selected the test mode from the operation panel 53. The description of the same components as those in the first embodiment, the copy operation, and the like is omitted, and the same components are denoted by the same reference numerals.

First, test image data previously stored in the ROM in the general control unit 54 is input to the laser control unit 59 shown in FIG. 5, and a predetermined fixing test image T is created in the same procedure as described above. Is performed (S11). Further, the surface temperature of the heating roller 112 when the OHP sheet S passes through the fixing device 40, that is, the fixing temperature is detected by the temperature sensor 222 (S12). Subsequently, the overall control unit 54 calls the test image data stored in the ROM and reads it (S13), and reads the read test image data and the surface temperature of the heating roller 212 detected by the temperature sensor 222 (S13). (Fixing temperature), the fixing test image T is fixed on the OHP sheet having the assumed standard fixing characteristics.
The standard intensity Ibr of the straight transmitted light is calculated (S14).

On the other hand, the transmitted light intensity information detecting section 43
The intensity Ib of the linearly transmitted light of the fixing test image T created on the P sheet S is measured, and this data is transmitted to the overall control unit 54.
(S15). Then, the overall control unit 54 compares the intensity Ib of the straight transmitted light with the standard intensity Ibr of the straight transmitted light calculated in S14, and estimates the fixing characteristics of the OHP sheet S based on the comparison result (S16). . This estimation is based on a seven-point scale (A to G ranks) as shown in Table 2.
Done in In other words, the fixing characteristics assumed in the copying machine 1 are set as the standard (D rank), and the evaluation is performed by being classified into three levels for the side where the fixing is easy and the side where the fixing is difficult.

[0055]

[Table 2]

Thereafter, the overall control unit 54 corrects the fixing speed in the fixing unit 40 based on the estimation result (A to G ranks) (S17). Specifically, the general control unit 54
Issues a correction instruction to the drive control unit 55, and based on this instruction, the drive control unit 55 changes the peripheral speed of the heating roller 212 as shown in Table 2. For example, when the general control unit 54 estimates that the fixing property of the OHP sheet S is E rank, the peripheral speed of the heating roller is changed from 80 mm / sec (standard setting value) to 72 mm / sec, which is 10% lower.

By such correction, an appropriate amount of heat is supplied according to the fixing characteristics of the OHP sheet S, and fixing is performed. Therefore, it is possible to obtain a fixed image in which sufficient translucency and coloring properties are secured. Therefore, it is possible to avoid unnecessary copying of the copy and use of an OHP sheet having a poor appearance.

As described in detail above, according to the copying machine of the second embodiment, a predetermined fixing test image T is created on the OHP sheet S periodically or by an operator's selection. Then, the transmitted light intensity information detecting section 4
3 measures the intensity Ib of the straight transmitted light of the fixing test image T. Then, the overall control unit 54 determines the intensity Ib of the straight traveling transmitted light detected by the transmitted light intensity information detecting unit 43, the test image data, and the heating roller 212 detected by the temperature sensor 222.
The fixing characteristic of the OHP sheet S is estimated by comparing with the standard intensity Ibr of the straight transmitted light of the fixing test image T calculated based on the surface temperature (fixing temperature). Thereafter, based on this estimation result, the overall control unit 54
The fixing speed in the fixing device 40 is corrected so that an appropriate amount of heat according to the fixing characteristics of the sheet S can be supplied. As a result, even when the OHP sheet S has characteristics different from the standard fixing characteristics, an appropriate amount of heat is supplied according to the fixing characteristics to perform fixing. Therefore, it is possible to obtain a fixed image in which sufficient translucency and coloring properties are secured.

(Third Embodiment) Next, a third embodiment will be described. The configuration of the copying machine according to the third embodiment is substantially the same as that of the copying machine 1 according to the first embodiment, but the fixing temperature in the fixing device is determined based on the fixing characteristics of the OHP sheet used. Instead of changing
The difference is that the fixing pressure is changed. That is, the pressing force of the pressure roller 213 against the heating roller 212 is changed. Accordingly, the configuration of the fixing device is also different. Therefore, the configuration of the fixing device in the copying machine according to the present embodiment and the control for changing the fixing pressure will be described. The description of the same components as those in the first embodiment, the copy operation, and the like is omitted, and the same components are denoted by the same reference numerals.

First, the configuration of the fixing device 140 is shown in FIG.
This will be described with reference to FIG. FIG. 12 is a side view of the fixing device 140. The fixing device 140 has basically the same configuration as the fixing device 40 in the first embodiment, except that the pressing force of the pressing roller 213 against the heating roller 212 can be changed. That is, these heating rollers 21
As shown in FIG. 12, the pressure roller 2 and the pressure roller 213 are supported by pressing support members 214 and 215 in a state where they can be pressed against each other and can rotate. Further, the pressing support member 215 is provided on the supporting shaft 216 with respect to the pressing supporting member 214.
To be rotatable. An elastic member 211 for pressing the pressing roller 213 against the heating roller 212 is provided below the pressing support member 215 that supports the pressing roller 213 in the drawing. Further, below the elastic member 211, a cam 21 connected to the drive motor M is provided.
0 is provided.

The change of the pressing force is performed by the cam 210.
Is rotated by the drive motor M by a predetermined angle. That is, by rotating the cam 210 counterclockwise, the contact pressure between the heating roller 212 and the pressure roller 213 can be increased because the elastic member 211 is compressed, and conversely, the cam 210 is rotated clockwise. By moving, the contact pressure between the heating roller 212 and the pressing roller 213 can be reduced because the elastic member 211 is extended.

Next, control for correcting the fixing pressure among the fixing conditions will be described with reference to the flowchart shown in FIG. The subroutine shown in this flowchart is performed after a predetermined number of copies have been made, after a predetermined operation time has elapsed, or when the operator has selected the test mode from the operation panel 53.

First, test image data previously stored in the ROM in the general control unit 54 is input to the laser control unit 59 shown in FIG. 5, and a predetermined fixing test image T is created in the same procedure as described above. Is performed (S21). The surface temperature of the heating roller 212 when the OHP sheet S passes through the fixing device 140, that is, the fixing temperature is detected by the temperature sensor 222 (S22). Subsequently, the overall control unit 54 calls the test image data stored in the ROM and reads it (S23), and reads the read test image data and the surface temperature of the heating roller 212 detected by the temperature sensor 122 (S23). (Fixing temperature), the standard intensity Ibr of straight transmitted light of the fixing test image T when the fixing test image T is fixed on the OHP sheet having the assumed standard fixing characteristics is calculated (S24).

On the other hand, the transmitted light intensity information detecting section 43
The intensity Ib of the linearly transmitted light of the fixing test image T created on the P sheet S is measured, and this data is transmitted to the overall control unit 54.
(S25). The overall control unit 54 compares the intensity Ib of the straight transmitted light with the standard intensity Ibr of the straight transmitted light calculated in S24, and estimates the fixing characteristics of the OHP sheet S based on the comparison result (S26). . This estimation is based on a seven-point scale (A to G ranks) as shown in Table 2.
Done in In other words, the fixing characteristics assumed in the copying machine 1 are set as the standard (D rank), and the evaluation is performed by being classified into three levels for the side where the fixing is easy and the side where the fixing is difficult.

[0065]

[Table 3]

Thereafter, the overall control unit 54 corrects the fixing speed in the fixing unit 140 based on the estimation result (A to G ranks) (S27). Specifically, the general control unit 5
4 issues an instruction to the drive motor M, and the drive motor M rotates the cam 210 by a predetermined angle based on the instruction, so that the pressing force of the pressure roller 213 against the heating roller 212 is shown in Table 3. Change to For example, when the general control unit 54 estimates that the fixing property of the OHP sheet S is B rank, the pressing force of the pressing roller 213 is set to 50 k.
g (standard setting value) to 25 kg, 50% lower.

By such correction, an appropriate amount of heat is supplied according to the fixing characteristics of the OHP sheet S, and fixing is performed. For this reason, good fixability is ensured, and a fixed image with sufficient translucency and color development can be obtained. Therefore, it is possible to avoid unnecessary copying of the copy and use of an OHP sheet having a poor appearance.

As described above in detail, according to the copying machine of the third embodiment, a predetermined fixing test image T is created on the OHP sheet S periodically or by an operator's selection. Then, the transmitted light intensity information detecting section 4
3 measures the intensity Ib of the straight transmitted light of the fixing test image T. Then, the overall control unit 54 determines the intensity Ib of the straight traveling transmitted light detected by the transmitted light intensity information detecting unit 43, the test image data, and the heating roller 212 detected by the temperature sensor 222.
The fixing characteristic of the OHP sheet S is estimated by comparing with the standard intensity Ibr of the straight transmitted light of the fixing test image T calculated based on the surface temperature (fixing temperature). Based on this estimation result, the overall control unit 54 corrects the fixing pressure in the fixing device 140 so that an appropriate amount of heat can be supplied according to the fixing characteristics of the OHP sheet S. This allows O
Even if the HP sheet S has characteristics different from the standard fixing characteristics, an appropriate amount of heat is supplied according to the fixing characteristics to perform fixing. Therefore, it is possible to obtain a fixed image in which sufficient translucency and coloring properties are secured.

(Fourth Embodiment) Next, a fourth embodiment will be described. The copying machine according to the fourth embodiment has substantially the same configuration as the copying machine 1 according to the first embodiment, but detects the transmitted light intensity information of the copied image without creating a test image. OH used
The difference is that the fixing characteristics of the P sheet are estimated. The fixing characteristic estimating program is executed after a predetermined number of copies have been made, after a predetermined operating time has elapsed, or when the operator has selected. Hereinafter, the fixing characteristic estimation processing will be described with reference to FIG. Note that the copy operation and the test image creation operation are the same as those in the first embodiment, and therefore description thereof is omitted, and the same components are denoted by the same reference numerals.

When the fixing characteristic estimating program is executed, first, the image reading section 2 obtains image data corresponding to the image of the document. Next, the areas R1, R2, in which the transmitted light intensity information detecting unit 43 can detect the transmitted light intensity information of the fixed image.
In R3, ..., in which area the fixed image (image data)
Check for the existence of For example, in the case shown in FIG. 14, it is found that the fixed image exists in the region R2. Then, the IR controller 51 issues a command to the transmitted light intensity information detector 43 via the overall controller 54 to detect transmitted light in the region R2. Next, a fixed image is formed on the OHP sheet S based on the image data obtained by reading the image of the document by the above-described electrophotographic process.

Then, at the timing when the OHP sheet S is discharged from the fixing device 40 and the area R2 reaches the detection area of the transmitted light intensity information detecting section 43, the transmitted light intensity information detecting section 4
3 measures the intensity Ig of the straight transmitted light of the fixed image G and transmits this data to the overall control unit 54. Further, from the data memory unit 9 provided in the image reading unit 2, the image data of the region R2 is transmitted to the general control unit 54. Further, the general control unit 54 reads the surface temperature (fixing temperature) of the heating roller 212 detected by the temperature sensor 222.

Then, based on the image data of the area R2 and the fixing temperature detected by the temperature sensor 222, the general control unit 54 sets the OHP having the assumed standard fixing characteristics.
The standard intensity Igr of the transmitted light when the fixed image G in the region R2 is fixed on the sheet is calculated. And the overall control unit 54
Is the intensity I of the straight transmitted light of the fixed image G in the region R2.
g and the standard strength Ibr, and the fixing characteristics of the OHP sheet S are estimated based on the comparison result. This estimation is performed in a seven-step evaluation (A to G ranks) as shown in Table 1. That is, the assumed fixing characteristics are set to the standard (D
As the rank, the side on which the image is easily fixed and the side on which the image is hardly fixed are each classified into three ranks for evaluation.

Thereafter, the overall control unit 54 corrects the fixing condition based on the estimation result (A to G ranks). Specifically, the control temperature of the heater lamp 221 is changed as shown in Table 1. Thus, an appropriate amount of heat is supplied according to the fixing characteristics of the OHP sheet to be used, and the fixing is performed. Therefore, it is possible to obtain a fixed image in which sufficient translucency and coloring properties are secured. Instead of changing the control temperature of the heater lamp 221, the rotation speed of the heating roller 212 may be changed as exemplified in the second embodiment, or may be exemplified in the third embodiment. As you did,
The pressing force of the pressure roller 213 against the heating roller 212 may be changed.

As described above in detail, according to the copying machine of the fourth embodiment, when the program for estimating the fixing characteristic of the OHP sheet is executed at a predetermined time or by the operator's selection, the original to be copied is copied. It is checked whether or not there is image data in an area that can be measured by the transmitted light intensity information detecting unit 43 from the image data of the transmitted light intensity, and if there is image data, its position (for example, the region R2) is investigated. Measures the intensity Ig of the straight transmitted light of the fixed image in the region R2. Then, the general control unit 54 sets the data of the intensity Ig of the straight transmitted light measured by the transmitted light intensity information detecting unit 43,
The image data corresponding to the region R2 stored in the data memory unit 9 and the heating roller 2 detected by the temperature sensor 122
The fixing characteristic of the OHP sheet S is estimated by comparing the standard intensity Ibr of the straight transmitted light of the fixed image G calculated based on the surface temperature (fixing temperature) of No. 12 with the standard temperature Ibr. Then, the overall control unit 54 corrects the fixing condition in the fixing device 40 based on the estimation result so as to supply an appropriate amount of heat according to the fixing characteristics of the OHP sheet S.

Thus, even if the OHP sheet S has characteristics different from the standard fixing characteristics, an appropriate amount of heat is supplied according to the fixing characteristics, and the fixing is performed.
Therefore, it is possible to obtain a fixed image in which sufficient translucency and coloring properties are secured. Another advantage is that the OHP sheet is not wasted because no test image is created.

The above-described embodiment is merely an example, and does not limit the present invention in any way. Needless to say, various improvements and modifications can be made without departing from the gist of the present invention. For example, in the above embodiment, the transmitted light intensity information detecting unit 43 detects the straight transmitted light of the fixed image, but instead of detecting the straight transmitted light, as shown in FIG. CCD in section 63
The sensor 62 is connected to the optical axis 41L of the halogen lamp 41 and the OH
By arranging it at a position deviated from the optical axis 41L of the halogen lamp 41 while allowing the intersection P with the P sheet S, the fixing test image T
May be detected.

This is because the transmitted light intensity information detecting section 63 can accurately estimate the fixing characteristics of the OHP sheet by detecting the intensity Ic of the refracted transmitted light of the fixing test image T. That is, although the refracted transmitted light has a narrower measurement range than the straight transmitted light, it has a negative correlation with the quality of the image state, and its value greatly changes depending on the quality of the image state. Can be easily performed. Further, the light emission intensity Ia of the halogen lamp 41 is also detected, and the ratio (Ib / Ia) between the two is calculated,
This may be used to estimate the fixing characteristics of the recording medium. In this case, the emission intensity Ia of the halogen lamp 41
This is because it is possible to eliminate the influence on the intensity Ic of the refracted transmitted light due to the fluctuation of the refraction.

As shown in FIG. 16, the CCD sensor 42 in the transmitted light intensity information detecting unit 73 is arranged coaxially with the optical axis 41L of the halogen lamp 41, and the CCD sensor 62 is connected to the optical axis 41L of the halogen lamp 41 and the OHP sheet. By disposing it at a position deviated from the optical axis 41L of the halogen lamp 41 while allowing for the intersection P with S, the transmitted light intensity information detecting unit 73 allows the intensity Ib of the straight transmitted light of the fixing test image T and the refraction transmission The light intensity Ic may be detected.

As described above, the transmitted light intensity information detecting section 73 detects the intensity Ic of the straight transmitted light Ib and the refracted transmitted light of the fixing test image T, thereby obtaining the intensity ratio between the straight transmitted light and the refracted transmitted light. By using this intensity ratio for estimating the fixing characteristics, the intensity becomes stronger against disturbances such as fluctuations in the emission intensity Ia of the halogen lamp 41, and the fixing characteristics of the recording medium can be more reliably estimated.

Further, in the above embodiment, the transmitted light intensity information detecting section 43 uses the halogen lamp 41 and the CC
Although only one set of D sensors 42 is provided, it goes without saying that two or more sets can be provided.

In the first to fourth embodiments described above, the case where only one of the fixing temperature, the fixing speed, and the fixing pressure among the fixing conditions is corrected is exemplified. Two or three of the fixing temperature, the fixing speed, and the fixing pressure may be simultaneously corrected so that the temperature and the fixing speed are simultaneously corrected. This is because, by correcting a plurality of conditions at the same time, the amount of heat can be more appropriately supplied to the recording medium. Further, in the above-described embodiment, a roller fixing system is exemplified as the contact heating fixing unit. However, the present invention is not limited thereto, and a belt fixing system may be used. Furthermore, in the above-described embodiment, an example in which the present invention is applied to a copying machine has been described.
The present invention can be applied to any device having a fixing device.

[0082]

As described above, according to the image forming apparatus of the present invention, the transmitted light intensity information detecting means detects the transmitted light intensity information of the fixed image fixed on the recording medium. Next, the characteristic estimating means, based on the image data of the fixed image, the fixing temperature detected by the fixing temperature detecting means, and the transmitted light intensity information of the fixed image detected by the transmitted light intensity information detecting means,
Estimate the fixing characteristics of the recording medium. Then the correction means
Based on the detection result by the transmitted light intensity information detecting means and the estimation result by the characteristic estimating means, the fixing condition in the contact heating fixing means is corrected so as to ensure good fixing performance. Thereby, an appropriate amount of heat according to the fixing characteristics of the recording medium is supplied to the recording medium. Therefore, even when a recording medium having a fixing property different from the setting is used, it is possible to obtain a fixed image in which sufficient translucency and coloring properties are secured.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a copying machine according to a first embodiment.

FIG. 2 is a sectional view showing a configuration of a fixing device in the copying machine of FIG.

FIG. 3 is a diagram illustrating a configuration of a transmitted light intensity information detecting unit in the copying machine of FIG. 1;

FIG. 4 is a diagram illustrating another configuration of the transmitted light intensity information detection unit.

FIG. 5 is a block diagram showing a part of a control circuit of the copying machine shown in FIG. 1;

FIG. 6 is a flowchart illustrating control for correcting a fixing condition according to a fixing characteristic.

FIG. 7 is a diagram showing a creation pattern of a test image.

FIG. 8 is a diagram showing a test image creation pattern.

FIG. 9 is a diagram showing a test image creation pattern.

FIG. 10 is also a diagram showing a test image creation pattern.

FIG. 11 is a flowchart illustrating control for correcting a fixing condition according to the second embodiment.

FIG. 12 is a side view of a fixing device in a copying machine according to a third embodiment.

FIG. 13 is a flowchart illustrating control for correcting a fixing condition according to the third embodiment.

FIG. 14 is a diagram for explaining a method of detecting transmitted light in a transmitted light intensity information detection unit in a copying machine according to a fourth embodiment.

FIG. 15 is a diagram illustrating another configuration of the transmitted light intensity information detection unit.

FIG. 16 is a diagram showing another configuration of the transmitted light intensity information detecting unit.

FIG. 17 is a diagram illustrating a state of transmitted light in a case where a toner has a good melting state.

FIG. 18 is a diagram illustrating a state of transmitted light when the melting state of the toner is poor.

[Explanation of symbols]

 5 Image Processing Unit 30 Photoconductor Drum 32Y, 32C, 32M, 32K Developing Device 33 Transfer Charger 34 Transfer Drum 40 Fixing Device 41 Halogen Lamp 42 CCD Sensor 43 Transmitted Light Intensity Information Detecting Unit 54 Overall Control Unit 212 Heating Roller 213 Pressurizing Roller 221 Heater lamp 222 Temperature sensor S OHP sheet T Fixing test image

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA09 DA12 DC02 DE02 DE07 DE10 EA12 EA18 EC03 EC06 ED25 EE03 EE04 EE08 2H033 AA03 AA06 BB01 BB34 BB37 CA04 CA07 CA16 CA18 CA36 CA39 CA44

Claims (3)

[Claims] 1. An image having image forming means for forming an unfixed image on a recording medium, and contact heating fixing means for fixing the unfixed image generated by the image forming means on the recording body by contact heating. In the forming apparatus, a fixing temperature detecting unit that detects a fixing temperature of the contact heating fixing unit, a light emitting element that irradiates light to a fixed image fixed on the recording medium by the contact fixing unit, and an irradiation from the light emitting element A transmitted light intensity information detecting unit comprising: a light receiving element for detecting intensity information of transmitted light transmitted through the recording body and the fixed image; image data corresponding to an unfixed image created by the image creating unit; Characteristic estimating means for estimating the fixing characteristic of the recording medium based on the fixing temperature detected by the temperature detecting means and the detection result of the transmitted light intensity information detecting means; Image forming apparatus characterized by having a fixing condition correction means for correcting the fixing conditions in the contact heat fixing means on the basis of the estimation result of a constant section. 2. The image forming apparatus according to claim 1, wherein the fixing condition correcting unit is configured to determine a fixing temperature in the contact heating fixing unit based on a result of estimation by the characteristic estimating unit.
An image forming apparatus, wherein at least one of a fixing speed and a fixing pressure is corrected. 3. A test image data memory according to claim 1, wherein said image creating means stores test image data for creating a predetermined test image on said recording medium. An image forming apparatus, wherein the transmitted light intensity detecting means detects transmitted light intensity information of a fixing test image fixed on the recording medium.