JP2002072779A - Image forming apparatus, control method for image forming apparatus, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the interruption of image formation due to a detection misjudgment of a reflection type OHP sensor and to correctly perform the image formation according to the kind of a recording sheet medium. SOLUTION: When the specification of whether or not the kind of the material of the recording sheet medium is an OHP sheet is different from the detection decision result, deciding whether the kind of the material of the recording sheet medium is an OHP sheet, obtained by detecting the fed recording sheet material by the OHP sensor, the image forming operation is switched; when the fed recording sheet medium already has an image formed on its reverse side, a CPU 401 judges that the material kind is not decided and performs control for forming an image on the recording sheet medium which is fed unconditionally without detecting and deciding the material kind nor switching the image formation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which an image forming section performs an image forming operation on a recording sheet medium fed by a feeding section, a control method of the image forming apparatus, and a storage medium. It is.

[0002]

2. Description of the Related Art An electrophotographic method for forming a copy image by transferring a toner latent image image on a transfer member to a recording sheet medium represented by plain paper (hereinafter simply referred to as a sheet medium) and then thermally fixing it. In an image forming apparatus,
It is also possible to form an image on a sheet medium having material properties other than plain paper, such as an OHP sheet.

However, when a high-quality and high-definition image forming apparatus such as a color electrophotographic image forming apparatus is required, various image forming operations such as transfer conditions and fixing conditions are required depending on the material of the sheet medium. It is necessary to switch the condition to the optimal set value.

Normally, such switching of the set values is realized by an operator designating a type according to the material in advance when setting a sheet medium, and switching conditions in various image forming operations in accordance with the designation. ing.

[0005] However, if the operator specifies an error in the sheet medium type, image formation is performed under different image conditions, so that high-quality and high-definition image formation operation may not be performed. Was.

Further, heat resistance of a certain type of OHP sheet may be extremely low, and when an image forming operation is performed on such an OHP sheet by designating an incorrect sheet medium type, the image forming apparatus may fail to operate. During the heat fixing process, the OHP sheet is fused to the fixing device, and in the worst case, the fixing device may be damaged.

In order to avoid such a worst case,
In a conventional electrophotographic image forming apparatus, an OHP detection sensor for determining whether or not an OHP sheet is provided immediately before image formation is provided.
If the detection result of the P detection sensor is different, that is, even though the operator sets the OHP sheet, the OHP
If an attempt is made to feed a sheet medium other than the OHP sheet, or conversely, if the operator attempts to feed an OHP sheet despite the fact that a sheet medium other than the OHP sheet has been set, image formation is promptly performed. It is usual to provide a protection means for stopping the operation.

On the other hand, the O which is implemented for such a purpose is
As the HP detection sensor, the sheet medium is an OHP sheet by providing a light emitting unit and a light receiving unit so as to narrow the conveyance path of the sheet medium, and calculating the transmittance of light from the light emitting unit from the amount of light received by the light receiving unit. In many cases, a so-called transmissive sensor was used to determine whether or not the sensor was used. However, in this case, the sensor shape had to be configured so that the light-emitting unit and light-receiving unit were separated from each other. There were many disadvantages in terms of cost and cost reduction.

Therefore, in recent years, light emitted from the light emitting section is reflected on the surface of the sheet medium passing through the transport path,
A reflected light is received by a light receiving unit located near the light emitting unit, and the reflectance of the light at that time is calculated from the amount of received light to determine whether or not the sheet medium is an OHP sheet. OHP sensors are increasingly used.

Such a reflection type OHP detection sensor can be said to be more advantageous than the transmission type in terms of miniaturization and cost reduction of the apparatus since the light emitting section and the light receiving section can be formed on the same unit. .

[0011]

However, in the above-mentioned reflection type OHP detection sensor, the reflectance of the OHP sheet is relatively close to the reflectance of the sheet medium on which the image is formed on the back surface. There is a fundamental problem that there is a possibility that both may be erroneously recognized.

The tendency becomes more remarkable especially for an image in which writing is performed on the entire surface of the image formed on the back surface, that is, a so-called “solid image”.

Therefore, an OHP for forming an image on the other side of a sheet medium having an image formed on one side is provided.
Incorrect recognition of the detection sensor may determine that the sheet medium type designation by the operator is different from the detection result of the OHP detection sensor, which may cause an unexpected stop of the image forming operation. There was a problem that there is.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the first to fourteenth inventions according to the present invention is to provide a recording sheet medium fed by a feeding unit. Whether or not the material type of the recording sheet medium is an OHP sheet, and whether the material type of the recording sheet medium is an OHP sheet by detecting the fed recording sheet medium with a reflection type OHP detection sensor If the result is different, the image forming operation is switched, and when the fed recording sheet medium has an image formed on the back surface, it is determined that the material type determination of the recording sheet medium is not performed. Then, without performing the detection determination of the material type of the recording sheet medium and the switching of the image formation, control is performed such that the image formation is performed on the recording sheet medium fed unconditionally. Piece For recording sheet medium but which is re-feed the image formed, already OHP during image formation surface
It is possible to prohibit the execution of the detection processing by the OHP detection sensor itself from the determination that it is determined that the sheet is not a sheet, thereby preventing interruption of image formation due to erroneous detection of the OHP detection sensor, An object of the present invention is to provide an image forming apparatus, a control method for the image forming apparatus, and a storage medium that can correctly form an image in accordance with the type of a recording sheet medium.

[0015]

According to a first aspect of the present invention, there is provided a feeding section (pickup rollers 339, 3 shown in FIG. 1).
38, 354, transport rollers 336, 337, registration rollers 355, transfer belt 333, paper discharge flapper 357, paper discharge path 358, back path 359, reversing roller 360, reversing path 361, two-sided path conveying roller 362, two-sided path 36
3, an image forming unit (the image forming unit 31 shown in FIG. 1) for the recording sheet medium fed by the re-feed roller 364).
7 to 320) in the image forming apparatus performing the image forming operation, a first specifying unit (shown in FIG. 4) for specifying whether the material type of the recording sheet medium fed by the feeding unit is an OHP sheet or not. Recording sheet medium type selection setting screen),
A determination means (an OHP sensor 36 shown in FIG. 5) which detects the recording sheet medium fed by the feeding section and determines whether or not the material type of the recording sheet medium is an OHP sheet.
7, the CPU 401 shown in FIG. 2), when the material type designation of the recording sheet medium by the first designation means and the judgment result of the material type of the recording sheet medium by the determination means are different, the image forming operation is switched. Means (CPU 401 shown in FIG. 2); determining means (CPU 401 shown in FIG. 2) for determining whether or not to perform the material type determination of the recording sheet medium by the determining means; When it is determined that the material type determination of the recording sheet medium is not performed, the material type determination of the recording sheet medium by the determination unit and the switching of the image forming operation by the switching unit are unconditionally performed. And a control unit (CPU 401 shown in FIG. 2) for controlling to form an image on the fed recording sheet medium.

According to a second aspect of the present invention, the switching means is configured such that the material type designation of the recording sheet medium by the first designating means is different from the material type determination result of the recording sheet medium by the determining means. , The image forming operation is interrupted.

According to a third aspect of the present invention, the determining means detects the amount of reflected light with respect to the irradiation light on the surface of the recording sheet medium fed by the feeding unit, and based on the detection result. A reflection-type detection type (OHP sensor 367 shown in FIG. 5) for determining the material type of the recording sheet medium, and the determining means determines whether the recording sheet medium fed by the feeding unit is on the back side. When the image has already been formed, it is determined that the determination of the material type of the recording sheet medium by the determination means is not performed.

According to a fourth aspect of the present invention, the feeding section reversely conveys a recording sheet on which an image is formed by the image forming section and can re-feed the recording sheet to the image forming section (FIG. 1).
, Two-sided path conveying rollers 362, two-sided path 363, re-feeding rollers 364, conveying rollers 336, 337, registration rollers 355), and the determination means is a recording sheet medium re-fed by the feeding section. Is to determine that the image has been formed on the back side, and to determine that the determination of the material type of the recording sheet medium by the determination means is not performed.

According to a fifth aspect of the present invention, there is provided a second designating means for designating that the back side of the recording sheet medium fed by the feeding section has already been formed with an image (recording shown in FIG. 10). And the determination unit determines that the back surface of the recording sheet medium has already been image-formed by the second specification unit. This is to determine that the material type determination of the recording sheet medium is not performed.

According to a sixth aspect of the present invention, there is provided a feeder (FIG. 1)
Pickup rollers 339, 338, 354, conveyance rollers 336, 337, registration rollers 355, transfer belt 333, paper discharge flapper 357, paper discharge path 358, back path 359, reversing roller 360, reversing path 361, double-sided path conveying roller 362 shown in FIG. An image forming unit (image forming units 317 to 320 shown in FIG. 1) performs an image forming operation on the recording sheet medium fed by the double-sided path 363 and the re-feed roller 364. First specifying means (recording sheet medium type selection setting screen shown in FIG. 4) for specifying whether or not the material type of the recording sheet medium fed by the feeding section is an OHP sheet; A determination unit that detects the fed recording sheet medium and determines whether the material type of the recording sheet medium is an OHP sheet (see FIG. 5). HP sensor 367, CP shown in FIG. 2
U401), and when the material type designation of the recording sheet medium by the first designation means and the material type determination result of the recording sheet medium by the determination means are different, a first switching means for switching the image forming operation (FIG. CPU 4 shown in 2
01) and a second switching unit (CPU 4 shown in FIG. 2) for switching the detection and determination method of the recording sheet medium by the determination unit.
01), determining means (CPU 401 shown in FIG. 2) for determining whether or not to switch the method of detecting and determining the recording sheet medium by the determining means by the second switching means. When a determination is made to switch the detection determination method of the recording sheet medium of the determination unit,
A control unit (CPU 401 shown in FIG. 2) for controlling to perform image formation on a recording sheet medium after performing the switching process by the second switching unit and the detection determination process by the determination unit; Things.

According to a seventh aspect of the present invention, the first switching means specifies the material type of the recording sheet medium by the first specifying means and determines the material type of the recording sheet medium by the determining means. Is different, the image forming operation is interrupted.

An eighth invention according to the present invention is characterized in that the determining means detects the amount of reflected light with respect to the irradiation light on the surface of the recording sheet medium fed by the feeding section, and based on the detection result. A reflection-type detection type (OHP sensor 367 shown in FIG. 5) for determining the material type of the recording sheet medium, and the determining means determines whether the recording sheet medium fed by the feeding unit is on the back side. When the image has already been formed,
It is to judge that the switching of the detection / judgment method of the recording sheet medium by the judging means by the second switching means is performed.

According to a ninth aspect of the present invention, when a fed recording sheet medium has an image formed on the back surface,
The second switching unit determines whether the OHP sheet is an OHP sheet based only on the margin width outside the image range on the back surface of the recording sheet medium on which an image has been formed, based on the detection determination method of the recording sheet medium by the determination unit. Switch to the method of doing.

According to a tenth aspect of the present invention, there is provided a second designating means for designating that the back side of the recording sheet medium fed by the feeding section has already been formed with an image (recording shown in FIG. 10). Screen for specifying the second side of both sides of the sheet media)
When the second designating means designates that the back surface of the recording sheet medium has already been subjected to image formation, the second switching means makes the decision means determine the detection of the recording sheet medium by the decision means. Is to be switched.

An eleventh invention according to the present invention is directed to a control method of an image forming apparatus in which an image forming unit performs an image forming operation on a recording sheet medium fed by a feeding unit. A first designation step (FIG. 1) for designating whether the material type of the fed recording sheet medium is an OHP sheet or not.
1 step S1101) and a determination step (step S1105 in FIG. 11) of detecting the recording sheet medium fed by the feeding unit and determining whether or not the material type of the recording sheet medium is an OHP sheet. S1106) and a switching step of switching the image forming operation when the material type specification of the recording sheet medium in the first specifying step and the material type determination result of the recording sheet medium in the determining step are different (step in FIG. 11). S1108) and a judging step of judging whether or not to judge the material type of the recording sheet medium in the judging step (step S1102 in FIG. 11).
And when it is determined in the determining step that the material type determination of the recording sheet medium in the determining step is not performed, the material type determination of the recording sheet medium in the determining step and the image forming by the switching step are performed. A step of forming an image on a recording sheet medium fed unconditionally without switching the operation (step S110 in FIG. 11)
3).

According to a twelfth aspect of the present invention, there is provided a method for controlling an image forming apparatus in which an image forming section performs an image forming operation on a recording sheet medium fed by a feeding section. A first designation step (FIG. 1) for designating whether the material type of the fed recording sheet medium is an OHP sheet or not.
1 step S1101) and a determination step (step S1105 in FIG. 11) of detecting the recording sheet medium fed by the feeding unit and determining whether or not the material type of the recording sheet medium is an OHP sheet. S1106) and a first switching step of switching the image forming operation when the material type designation of the recording sheet medium in the first designation step and the material type determination result of the recording sheet medium in the determination step are different. 11 step S1108), a second switching step of switching the detection and determination method of the recording sheet medium in the determination step, and switching of the detection and determination method of the recording sheet medium in the determination step by the second switching step. A determination step of determining whether or not to perform (Step S1 in FIG. 11)
104), when it is determined in the determining step that the switching of the detection method of the recording sheet medium in the determining step is to be performed, the switching processing in the second switching step and the detection determination in the determining step After processing,
Step of Forming an Image on a Recording Sheet Medium (FIG. 11)
Step S1105).

According to a thirteenth aspect of the present invention, there is provided an image forming apparatus in which an image forming section performs an image forming operation on a recording sheet medium fed by a feeding section. A first designation step (step S1 in FIG. 11) for designating whether or not the material type of the recording sheet medium is an OHP sheet
101), the recording sheet medium fed by the feeding section is detected, and the material type of the recording sheet medium is set to OH.
A determination step of determining whether or not the sheet is a P sheet (steps S1105 and S1106 in FIG. 11); a specification of a material type of a recording sheet medium by the first specifying step; and a determination result of a material type of the recording sheet medium in the determination step If they are different, a switching step of switching the image forming operation (step S1108 in FIG. 11) and a determining step of determining whether to perform the material type determination of the recording sheet medium in the determining step (step S1102 in FIG. 11) And when it is determined in the determining step that the material type determination of the recording sheet medium in the determining step is not performed, the material type determination of the recording sheet medium in the determining step and the image forming by the switching step are performed. Step of forming an image on a recording sheet medium fed unconditionally without switching the operation (see FIG. 11). -Up S1103) a program for executing the one in which the computer storage media were able to store read.

According to a fourteenth aspect of the present invention, there is provided an image forming apparatus in which an image forming unit performs an image forming operation on a recording sheet medium fed by a feeding unit. A first designation step (step S1 in FIG. 11) for designating whether or not the material type of the recording sheet medium is an OHP sheet
101), the recording sheet medium fed by the feeding section is detected, and the material type of the recording sheet medium is set to OH.
A determination step of determining whether or not the sheet is a P sheet (steps S1105 and S1106 in FIG. 11); a specification of a material type of a recording sheet medium by the first specifying step; and a determination result of a material type of the recording sheet medium in the determination step Are different from each other, a first switching step of switching the image forming operation (step S1108 in FIG. 11), a second switching step of switching the detection method of the recording sheet medium in the determination step, and the second switching step A determining step (step S1104 in FIG. 11) of determining whether or not to switch the method of detecting and determining the recording sheet medium in the determining step in the determining step; and detecting the recording sheet medium in the determining step in the determining step. When it is determined that the determination method is to be switched, the switching process in the second switching process and the detection determining process in the determining process are performed. After performing step S11 in step (FIG. 11 for forming an image onto a recording sheet medium
05) is stored in a storage medium in a computer-readable manner.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A basic configuration of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a cross-sectional view illustrating the overall configuration of an image forming apparatus according to an embodiment of the present invention. This image forming apparatus includes a color reader unit 900 and a color printer unit 1.
000.

First, the configuration of the color reader unit 900 will be described.

In the color reader section 900, 101 is a CCD and 311 is a substrate on which the CCD 101 is mounted. A control unit 300 controls the entire image forming apparatus. Reference numeral 312 denotes an image processing unit, which includes a portion excluding the CCD 101 of the image processing unit shown in FIG. 2 described later, and a binary conversion unit 201 and delay units 202 to 205 shown in FIG.

An original 301 is placed on an original platen glass (platen). A document feeder (DF) 302 sequentially feeds a bundle of documents placed on a document table (not shown) onto a document table glass 301. The document feeder 302
Instead of this, there is also a configuration in which a mirror pressure plate (not shown) is mounted. 3
Numerals 03 and 304 denote light sources (halogen lamps or fluorescent lamps) for illuminating the original. 305 and 306 are reflecting umbrellas for condensing the light from the light sources 303 and 304 onto the document. Reference numeral 314 denotes the halogen lamps 303 and 304 and the reflectors 305 and 306.
And 315, a carriage that houses the mirrors 308 and 309. In addition,
The carriage 314 is moved at a speed V, and the carriage 315 is moved at a speed V / 2, and mechanically (motor 3) is perpendicular to the electrical scanning (main scanning) direction of the CCD 101 (in the direction of the arrow in the drawing).
By scanning (by the drive of No. 16), the entire surface of the document is scanned (sub-scan).

Reference numeral 310 denotes a lens which condenses reflected light or projected light from a document on the CCD 101. As described above, the document on the platen glass 301 reflects light from the light sources 303 and 304, and the reflected light is guided to the CCD 101 and converted into an electric signal. Even the ones that are placed in-line in RGB order on the top are 3-line CCDs, each with an R filter,
A G filter and a B filter may be arranged for each CCD, or the filters may be on-chip or
The filter may have a different structure from the CCD.)

The electric signal (analog image signal) converted by the CCD 101 is input to the image processing unit 312, where the image processing is performed.

Reference numeral 313 denotes an external interface (I / F) for a computer or the like.

The configuration of the control unit 300 and the digital image processing unit 312 shown in FIG. 1 will be described below with reference to FIGS. The color printer 1000 will be described later.

FIG. 2 is a block diagram showing the configuration of the control unit 300 shown in FIG. 1, and the same components as those in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 2, the control unit 300 exchanges information for controlling the digital image processing unit 312 and the printer control I / F unit 353 with each other.
/ F with CPU 401, operation unit 402, memory 40
3.

The operation unit 402 is composed of a liquid crystal display unit with a touch panel for inputting processing execution contents by the operator, information on processing for the operator, and notification of warnings and the like.

The memory 403 includes a ROM and RA
M, and the CPU 401
Based on the program stored in M, the entire image forming apparatus is totally controlled. The RAM in the memory 403 is a CPU
It is used as a work area 401.

FIG. 3 is a block diagram showing the configuration of the digital image processing section 312 shown in FIG. 1. The same components as those in FIG. 1 are denoted by the same reference numerals.

As described above, the original on the original platen glass 301 reflects light from the light sources 303 and 304, and the reflected light is guided to the CCD 101 and converted into an electric signal. Then, the electric signal (analog image signal) is input to the image processing unit 312.

As shown in FIG. 3, the electric signal input from the CCD 101 is clamped & amp. & S / H & A /
The sample and hold (S / H) is performed in the D section 102, and the dark level of the analog image signal is clamped to the reference potential.
The signal is amplified to a predetermined amount (the processing order is not limited to the notation order), A / D converted, and converted into, for example, an RGB 8-bit digital signal.

The RGB signals are output to the shading unit 1.
03, after shading correction and black correction are performed,
In the connection & MTF correction & document detection unit 104, the CCD 10
If 1 is a 3-line CCD, the splicing process differs in the reading position between the lines. Therefore, the delay amount for each line is adjusted according to the reading speed, and the signal timing is corrected so that the reading positions of the three lines become the same. In the MTF correction, the reading MTF changes depending on the reading speed and the magnification, so that the change is corrected, and in the document detection, the document size is confirmed by manipulating the document on the platen glass 301.

The digital signal whose read position timing has been corrected is input to the CCD 10 by the input masking unit 105.
1 and the light sources 303 and 304 and the reflector 30
The spectral characteristics of 5,306 are corrected.

The output of the input masking unit 105 is
/ F signal is input to the selector 106 which can be switched. The signal output from the selector 106 is subjected to color space compression &
It is input to the background removal & LOG conversion unit 107 and background removal unit 115.

After the signal input to the background removal 115 is removed, the signal is input to a black character determination unit 116 for determining whether or not the character is a black character in the document, and a black character signal is generated from the document.

Further, the color space compression & background removal & LOG conversion unit 107 to which the output of the other selector 106 is input.
Then, color space compression determines whether the read image signal is within the range that can be reproduced by the printer, and if so, corrects it so that it is within the range that the image signal can be reproduced by the printer. .

Then, a background removal process is performed, and the RGB signals are converted into CMY signals by LOG conversion. The timing of the signal generated by the black character determination unit 116 and the output signal of the color space compression & background removal & LOG conversion unit 107 for correcting timing are adjusted by the delay unit 108. The two types of signals are subjected to moiré removal by the moiré removal unit 109 and subjected to scaling processing in the main scanning direction by the scaling unit 110.

Reference numeral 111 denotes a UCR & masking & black character reflection unit, and the CMY signal processed by the scaling unit 110 is UC
A CMYK signal is generated by the R processing, corrected by the masking processing unit to a signal that was output from the printer, and a determination signal generated by the black character determination unit 116 is fed back to the CMYK signal. The signal processed by the UCR & masking & black character reflection unit 111 is subjected to density adjustment by the γ correction unit 112 and then subjected to smoothing or edge processing by the filter unit 113.

The signal processed as described above is converted from an 8-bit multi-level signal into a binary signal by a binary converter 201 shown in FIG. (The conversion method may be any of the dither method, the error diffusion method, and the improved error diffusion method.)
The configuration of the color printer unit 1000 will be described with reference to FIG. Hereinafter, the configuration and operation will be described.

In the color printer unit 1000, 35
Reference numeral 3 denotes a printer control I / F, and a color reader unit 900
Of the control signal from the CPU 401 shown in FIG. The color printer unit 1000 has a printer control I / F3.
The operation described below is performed based on the control signal from 53.

Next, the image forming section will be described in detail.

317 is a magenta (hereinafter, M) image forming section, 318 is a cyan (hereinafter, C) image forming section, 319 is a yellow (hereinafter, Y) image forming section, and 320 is a black (hereinafter, K) image forming section. The image forming units 317 to 32
Since the configuration of 0 is the same, the M image forming unit 317 will be described in detail, and the description of the other image forming units will be omitted.

In the M image forming unit 317, reference numeral 342 denotes a photosensitive drum, on which a latent image is formed by light from the LED array 210.

Reference numeral 321 denotes a primary charger, which is a photosensitive drum 342.
Is charged to a predetermined potential to prepare for latent image formation. A developing device 322 develops the latent image on the photosensitive drum 342 to form a toner image. Note that the developing device 322 has a sleeve 3 for applying a developing bias to perform development.
95 are included.

Reference numeral 323 denotes a transfer charger, which is a transfer belt 333.
, The toner image on the photosensitive drum 342 is transferred to a recording paper or the like on the transfer belt 333. Since the image forming apparatus of the present embodiment has good transfer efficiency, no cleaner section is provided. (It goes without saying that there is no problem even if the cleaner is mounted.) Next, a procedure for forming an image on a recording sheet medium will be described.

First, the operation of transporting the recording sheet medium in the paper feed unit will be described.

The recording sheet media stored in the cassettes 340 and 341 and the manual paper feed unit 368 are conveyed one by one onto a paper feed path by the pickup rollers 339, 338 and 354. Here, the type of the recording sheet medium, that is, whether the sheet medium is an OHP sheet or another sheet medium can be set by the operator via the operation unit 402 (FIG. 4).

FIG. 4 shows a setting screen for the type of recording sheet medium (OHP sheet or plain paper (recording sheet medium other than OHP sheet)) displayed on the liquid crystal display unit of the operation unit 402 shown in FIG. FIG. 4 is a schematic diagram showing an example of a recording sheet medium for selecting and setting the type of recording sheet medium, that is, whether it is OHP paper (OHP sheet) or plain paper (recording sheet medium other than OHP sheet). This corresponds to a sheet medium type selection setting screen. Note that the user is
By selecting either the paper key 802 or the plain paper (recording sheet medium other than the OHP sheet) key 801,
The type of the recording sheet medium can be set.

Hereinafter, the operation of conveying the recording sheet medium described above will be continued with reference to FIG.

Pickup rollers 339, 338, 35
When the recording sheet medium is conveyed onto the paper feeding path by the printer 4, the recording sheet medium on the paper feeding path is transported by the conveying rollers 33.
6,337 and delivered to the registration roller 355,
The registration sensor 356 immediately before that detects passage of the recording sheet medium. In the present embodiment, when the passage of the recording sheet medium is detected by the registration sensor 356, the transport operation is temporarily interrupted after the passage of an appropriate time. As a result, the recording sheet medium collides with the stopped registration roller 355 and the conveyance is stopped. At this time, the position of the recording sheet medium is fixed so that the end of the recording sheet medium in the traveling direction is perpendicular to the conveyance path, and the recording is performed. The conveyance direction is corrected when skew occurs due to the conveyance direction of the sheet medium being displaced from the conveyance path. This process is generally called register registration.

The registration is indispensable for minimizing the deviation of the image forming direction with respect to the subsequent recording sheet medium.
In addition, a time from when the registration sensor 356 is detected until registration is performed is hereinafter referred to as a registration stop waiting time t _reg .

Here, in this embodiment, the OHP sensor 367 disposed on the near side (upstream) with respect to the mounting position of the registration sensor 356 on the transport path causes the recording sheet medium to be O
With the HP sensor 367, it is possible to identify whether or not the recording sheet medium is an OHP sheet.
The identification operation will be described below with reference to FIGS.

First, the configuration of the OHP sensor 367 will be described in detail with reference to the configuration diagram of FIG.

FIG. 5 shows the OHP sensor 367 shown in FIG.
FIG. 3 is a diagram showing the configuration of FIG.

As shown in FIG.
The P sensor 367 includes a light emitting unit 501 that converts an electric signal into light by a light emitting diode and emits light, and a light receiving unit 502 that converts light into an electric signal by a light emitting conversion element.

Subsequently, the OHP sensor 3 having the configuration shown in FIG.
The OHP sheet identification operation of No. 67 will be described in detail with reference to FIG.

FIG. 6 shows the OHP sensor 367 shown in FIG.
FIG. 9 is a diagram for explaining the OHP sheet identification operation of FIG.

The light emitting section 501 can emit light at an arbitrary timing. If the recording sheet medium is located within the reach of the light emitted from the light emitting section 501, the recording sheet medium is The arriving light is reflected by the surface and received by the light receiving section 502. The reflection characteristics at this time differ depending on whether the recording sheet medium is plain paper or an OHP sheet.

FIG. 6A shows a case where the recording sheet medium is an OHP sheet.

As shown in FIG. 6A, when the recording sheet medium is an OHP sheet, light is transmitted through the surface of the sheet medium, so that the amount of reflected light received by the light receiving unit 502 is small.

FIG. 6B shows a case where the recording sheet medium is plain paper.

As shown in FIG. 6B, when the recording sheet medium is plain paper, most of the light reaching the surface of the sheet medium is reflected by the surface, so that the amount of reflected light received by the light receiving unit 502 Becomes larger.

The difference between the current values photoelectrically converted by the light receiving unit 502 in accordance with the amount of reflected light causes the recording sheet medium to become OH.
It is possible to identify whether the sheet is a P sheet.

Hereinafter, referring to the flowchart of FIG.
The procedure for identifying plain paper and OHP in the image forming apparatus of the present invention will be described.

FIG. 7 is a flowchart showing an example of a first control processing procedure in the image forming apparatus of the present invention.
This corresponds to the plain paper, OHP identification processing procedure. This process is executed by the CPU 401 shown in FIG. 2 based on a program stored in a ROM (not shown) of the memory 403 or another storage medium (not shown).

First, in step S701, feeding of a recording sheet medium is started.

The fed recording sheet medium is conveyed along the paper supply path and reaches the registration rollers 355, but before that, the passage of the recording sheet medium is always detected by the registration sensor 356.

In step S 702, the registration sensor 356 is started after a certain period of time when the passage of the sheet medium at the start of feeding is predicted.
It monitors whether or not is detected. In step S702, when the detection of the passage of the sensor is performed, step S7
At 03, a first OHP sensor detection process is performed.

In step S703, an OHP sheet identification operation of the OHP sensor 367 is executed as a first OHP sensor detection process. Since the details of the OHP sheet identification operation have been described above, they are omitted here.

At this time, if the amount of reflected light is large as a result of the discriminating operation, the variable a = 1 for the first OHP sensor detection processing result is set, and if the amount of reflected light is small, a = 0 is set. Note that the recording sheet medium is continuously conveyed on the paper feeding path even during the execution of the first OHP sensor detection processing in step S703.

Thereafter, in step S704, registration is performed after the registration stop waiting time t _reg , and the conveyance of the recording sheet medium is temporarily stopped.

At the point of time when the cash register has been taken, step S7
At 05, a second OHP sensor detection process is performed.

In step S705, an OHP sheet identification operation of the OHP sensor 367 is executed as a second OHP sensor detection process. The OHP sheet identification operation is the same as the case of the first OHP sensor detection process, and thus will not be described here. In the second OHP sensor detection process, in the first OHP sensor detection process, if the amount of reflected light is large as a result of the identification operation at this time, the second sensor detection process result variable b
= 1, and b = 0 if the amount of reflected light is small.

Finally, in step S706, the first and second
From the OHP sensor detection process result variables a and b, it is determined whether the recording sheet medium is an OHP sheet or not. In this determination, considering that the reflectance of the OHP sensor with respect to the OHP sheet is unstable, 2
If it is determined that the sheet is an OHP sheet at least once in the degree detection process, it is determined that the sheet is an OHP sheet. That is, only in the case of (a = 1, b = 1), it is determined that the recording sheet medium is a recording sheet medium other than the OHP,
Other combinations (a = 0, b = 1), (a = 1,
For (b = 0) and (a = 0, b = 0), it is determined that the sheet is an OHP sheet.

In this embodiment, if the determination result is different from the type of the recording sheet medium set by the operator at the start of feeding, it is determined that the setting by the operator is defective, and the feeding operation is performed. Interrupt immediately.

When such an interrupting process of the image forming operation is performed, the operator is notified by a liquid crystal display on the operation unit 402, and the cassette 340,
341 and a warning to remove the recording sheet medium other than the designated one stored in the manual paper feed unit 368 (FIG. 8).

FIG. 8 is a schematic diagram showing an example of a warning message displayed on the liquid crystal display unit of the operation unit 402 shown in FIG. 2, and the judgment result of the recording sheet medium is determined in advance by the operator at the start of sheet feeding. When the type of the recording sheet medium is different from the set type, the operation unit 4
02 corresponds to the warning message displayed on the liquid crystal display unit. Note that the CPU 401 can confirm that the user has viewed the warning message by pressing the confirmation key 901 by the user.

Hereinafter, the procedure for forming an image on a recording sheet medium will be continued with reference to FIG.

After the registration is temporarily stopped, the recording sheet medium during which the registration is stopped is fed onto the transfer belt 333 by the feeding rollers 336 and 337 and the registration roller 355.

The recording sheet medium fed on the transfer belt 333 is charged by the attraction charger 346.

Reference numeral 348 denotes a transfer belt roller which drives the transfer belt 333 and charges the plain paper or the like in a pair with the attraction charger 346 to attract the plain paper or the like to the transfer belt 333. A recording sheet medium leading edge sensor 347 detects the leading end of plain paper or the like on the transfer belt 333. In addition,
The detection signal from the recording sheet medium leading edge sensor 347 is sent from the printer unit 1000 to the color reader unit 900, and is used as a sub-scanning synchronization signal when a video signal is sent from the color reader unit 900 to the printer unit 1000.

Thereafter, the recording sheet medium is transferred to the transfer belt 3.
The toner image is formed on the surface of the image forming units 317 to 320 in the order of MCYK. The plain paper or the like that has passed through the K image forming unit 320 is easily separated from the transfer belt 333 by the charge removing charger 3.
After the charge is removed at 49, the sheet is separated from the transfer belt 333.

Reference numeral 350 denotes a peeling charger, which prevents image disturbance due to peeling discharge when plain paper is separated from the transfer belt 333. The separated plain paper is charged with a pre-fixing charger 3 in order to compensate for toner attraction and prevent image disturbance.
After the toner is charged at 51 and 352 and the toner image is thermally fixed by the fixing unit 334, the transport path is switched to the paper discharge path 358 by the paper discharge flapper 357, and the paper is discharged to the paper discharge tray 335 as it is.

FIG. 9 shows the color printer unit 1 shown in FIG.
FIG. 3 is a block diagram illustrating a detailed configuration of a printer processing unit of the printer.

Hereinafter, the LED image recording will be described with reference to FIG.

The binary MCYK image signal generated by the image processing unit shown in FIG.
7 is a signal generated by the binary conversion unit 201 on the basis of the paper leading edge signal from FIG. 7, and by adjusting the difference in the distance between the paper leading edge sensor and each image forming unit by the delay units 202 to 205, Colors can be printed at positions.

At predetermined timings, the delay units 202 to 205
The image signals read out from the LED driving units 206-2
09, and the LED driving units 206 to 209
A signal for driving D210 to D213 is generated.

In the present embodiment, the recording sheet medium on which an image has been generated by the image forming means is reversely conveyed and automatically fed again to the image forming means, so that the back surface of the recording sheet medium is Image formation can be performed continuously.

Subsequently, the operation for forming an image on the back surface of the recording sheet medium will be described in detail.

When forming an image on the back surface of the recording sheet medium, first, an image is formed on the front surface of the recording sheet medium. The operation of forming an image on the front surface has been described above, and will not be described here. However, if the image is formed only on the front surface, the toner image is thermally fixed by the fixing unit 334 after the image formation, and then discharged by the discharge flapper 357. Paper path 35
The transfer path is switched to the side 8 and the discharge tray 33 is left as it is.
In the case where image formation on the front surface is to be performed subsequently, the conveyance path is switched to the back path 359 by the discharge flapper 357, and the reversing roller 360 is adjusted accordingly.
The recording sheet medium is inverted by the rotation of
Once transported inside.

Thereafter, the recording sheet medium is once conveyed into the reversing path 361 by the width of the sheet medium in the feeding direction, and then the reverse reversal drive of the reversing roller and the double-sided path
By the drive of 62, the image is conveyed to the double-sided path 363 with the image formed on the surface facing downward.

When the recording sheet medium is conveyed toward the re-feed roller 364 on the double-sided path 363, the passage of the recording sheet medium is detected by the re-feed sensor 365 immediately before. In this embodiment, when the passage of the recording sheet medium is detected by the re-feed sensor 365, the conveyance operation is temporarily interrupted after an appropriate time has elapsed. As a result, the recording sheet medium collides with the stopped re-feed roller 364, and the conveyance is temporarily stopped. At this time, the position of the recording sheet medium is fixed so that the end of the recording sheet medium in the traveling direction is perpendicular to the conveyance path. When the skew occurs due to the conveyance direction of the recording sheet medium being deviated from the conveyance path in the re-feed path, the conveyance direction of the re-feed path is corrected. This process is usually referred to as re-feed registration.

This re-feed registration is indispensable for minimizing the inclination of the image forming direction with respect to the back surface of the recording sheet medium thereafter.

After the re-feeding registration is completed, the re-feeding roller 364 is activated to convey the recording sheet medium onto the re-feeding path 366 and the feeding path in a state where the recording medium is turned upside down. Subsequent image forming operations are the same as the above-described front surface image forming operations, and will not be described here. In this way, the recording sheet medium on which the images are formed on both the front and back sides is directly switched to the discharge path 358 by the discharge flapper 357, and the discharge flapper 33 is directly changed.
5 is discharged.

As described above, in this embodiment, if the result of detection by the reflection type OHP detection sensor is different from the designation of the recording sheet medium, the image forming operation is immediately stopped. However, in the reflection type OHP detection sensor used in the present embodiment, since the reflectance of the OHP sheet and the reflectance of the recording sheet medium on which the image is formed on the back surface are relatively close, both are wrong. There is a fundamental problem that it may be confirmed.

In particular, the tendency is more remarkable for an image in which writing is performed on the entire surface of the image formed on the back surface, that is, a so-called “solid image”.

For this reason, when an image is formed on the other side of a recording sheet medium on which an image is formed on one side, an erroneous confirmation of the OHP detection sensor causes the operator to specify the type of the recording sheet medium and detect the OHP detection sensor. The result may be determined to be different, in which case the process may be interrupted without forming an image on the back side of a recording sheet medium other than the OHP sheet on which an image can be originally formed. There is.

Therefore, in the present embodiment, the above-described erroneous processing is performed by prohibiting the above-described OHP detection processing or changing the OHP detection processing procedure based on the determination described below. To avoid it.

Referring to FIGS. 10 and 11, a description will now be given of the process of inhibiting the above-described OHP detection process or changing the OHP detection process procedure.

FIG. 10 is a schematic diagram showing an example of a screen for designating the second side of both sides of the recording sheet medium displayed on the liquid crystal display unit of the operation unit 402 shown in FIG.
The recording sheet medium set in the paper feed unit 41 and the manual sheet feeding unit 368 corresponds to a selection setting screen for determining whether or not an image is already formed on the front surface of the recording sheet medium other than the OHP sheet.

In the figure, reference numeral 1001 denotes a “yes” key.
This button is pressed when the recording sheet medium set in the cassettes 340 and 341 and the manual sheet feeding unit 368 is a recording sheet medium other than the OHP sheet, and an image has already been formed on the front surface. A “No” key 1002 is pressed when the set recording sheet medium is an OHP sheet or when no image is formed on the front surface.

FIG. 11 is a flowchart showing an example of the second control processing procedure in the image forming apparatus according to the present invention, and corresponds to a processing procedure for inhibiting the OHP detection processing or changing the OHP detection processing procedure. S110
1 to S1109 indicate each step.

First, as “preparation processing”, step S 1
In 101, the recording sheet medium set in the cassettes 340 and 341 and the manual feed unit 368 is
Sheet or plain paper (other than OHP sheet)
The operator specifies on the recording sheet medium type selection setting screen shown in FIG. 4 of the operation unit 402, and furthermore, if the set recording sheet medium is other than the OHP sheet and an image has already been formed on the surface. If the setting has been made, the operator sets that effect through the double-sided second surface designation screen of the operation unit 402 shown in FIG.

As the subsequent “image forming process”, the following judgment is made immediately before the OHP detection process is performed on each recording sheet medium.

First, in step S1102, it is determined whether or not the target recording sheet medium has been conveyed from the re-feeding path 366, and the target recording sheet medium has been conveyed from the re-feeding path 366. If it is determined that the OHP sheet is not an OHP sheet at the time of image formation on the front surface, the execution of the detection processing by the OHP detection sensor is prohibited in step S1103. , The image forming processing operation is continued unconditionally.

On the other hand, if it is determined in step S1102 that the target recording sheet medium has not been conveyed from the re-feeding path 366, the process proceeds to step S1104.
Move to

In step S1104, the previous step S
At 1101, it is determined whether or not a setting has been made that the back side image has already been formed, and the setting has been made that the back side image has already been formed ("Yes" in FIG. 10).
If the key 1001 has been selected and set), an OHP detection process is performed in step S1105 in accordance with a special processing procedure for a recording sheet medium on which a backside image has already been formed, and the flow advances to step S1107.

On the other hand, in step S1104, it is not set in step S1101 that the back side image has already been formed ("NO" key 10 in FIG. 10).
02 has been selected and set), in step S1106, the normal O described in detail above.
An HP detection process is performed, and the process proceeds to step S1107.

Next, in step S1107, the paper type (OHP sheet or plain paper) of the recording sheet medium designated by the operator in step S1101 and the fed recording sheet detected and determined in step S1105 or S1106. It is determined whether or not the medium type (OHP sheet or plain paper) matches, and if it is determined that the medium type matches, the image forming processing operation is continued as it is, and the image forming processing ends.

On the other hand, in step S1107, step S1107 is executed.
The paper type (OHP sheet or plain paper) of the recording sheet medium designated by the operator in 1101 and the paper type (OHP sheet or plain paper) of the fed recording sheet medium detected and determined in step S1105 or S1106. If it is determined that is different (does not match), in step S1108, the image forming processing operation is interrupted, and step S110 is performed.
At 9, the warning message shown in FIG. 8 is displayed.

The special OHP identification processing means for the recording sheet medium on which the back side image has already been formed in the above-described step S1105 means that the image is always formed on the back side of the recording sheet medium on which the image has been formed. This detection method is based on the premise that there is a margin of several millimeters outside the range, and is different from the normal OHP detection processing described in FIG.
The second OHP sensor detection processing in step 705 is omitted, and only the value of the first sensor detection processing result variable a is noted in the determination processing in step S706, and a = 0.
In this case, it is determined that the sheet is an OHP sheet, and when a = 1, it is determined that the sheet is not an OHP sheet.

That is, this is because OH is determined by the determination result only for the recording sheet medium and the margin at the leading end.
It means to determine whether the sheet is a P sheet,
By doing so, it is possible to correctly determine whether or not the recording sheet medium on which the image is formed on the back surface is an OHP sheet. [Other Embodiments] In the above embodiment, when the determination result by the OHP detecting means is different from the type of the recording sheet medium set in advance by the operator at the time of starting the sheet feeding, the sheet feeding operation is immediately interrupted. However, the operation according to the determination result is not particularly limited. For example, (1) the recording sheet medium being fed is discharged and stopped later. (2) It is of course possible to perform an operation such as displaying the warning to the operator 402 only without stopping the operation, and of course.

In the above embodiment, step S11
At 05, the OHP detection processing is performed according to a special processing procedure for a recording sheet medium on which a backside image has already been formed, but the emphasis is placed on the purpose of avoiding erroneous OHP detection. And step S110
Similarly to 3, the execution of the detection process by the OHP detection sensor itself may be prohibited and replaced, and the image forming operation may be continued unconditionally as it is. Prohibition "/" Execution of special OHP detection process for sheet with backside image formed "
May be configured to be selectable.

As described above, in the case where the recording sheet medium on which one side of the image is formed is reversely conveyed and the automatic reverse refeeding means for automatically feeding the recording sheet medium again to the image forming section is provided, the automatic reversing re-feeding means is provided. For the recording sheet medium re-fed by the sheet feeding means, it is determined that the sheet is not an OHP sheet when the front side image is formed.
By prohibiting the execution of the detection process itself by the HP detection sensor, it is possible to form an image correctly without erroneous detection of the detection of the OHP sensor.

Further, in the case where the recording sheet medium having an image formed on one side is turned over as a recording sheet medium and the operator can set it again in the sheet feeding port, such as a manual sheet feeder, An interface is provided so that it is possible to specify that a recording sheet medium on which a backside image has been formed is set, and the OHP sensor detects the recording sheet medium fed when the designation is made. By prohibiting the execution of processing itself, OH
It is possible to form an image correctly without erroneous determination of P sensor detection.

Further, in the case where the recording sheet medium having an image formed on one side is turned over as a recording sheet medium and the operator can set it again in the sheet feeding port, such as a manual sheet feeding, the operator is required to An interface is provided so that it is possible to specify that the recording sheet medium on which the backside image has been formed is set. For the recording sheet medium fed when the designation is made, the image is already formed. An OHP sheet is determined by using only a margin width outside the image range on the back surface of a recording sheet medium.
By switching the sheet detection determination method, it is possible to form an image correctly without erroneous determination of OHP sensor detection.

In FIG. 1, the color printer unit 1
Although the case where the LED 000 is the LED method has been described, another electrophotographic method such as a laser beam method may be used.

Hereinafter, the configuration of a data processing program readable by the image forming apparatus according to the present invention will be described with reference to a memory map shown in FIG.

FIG. 12 is a view for explaining a memory map of a storage medium for storing various data processing programs readable by the image forming apparatus according to the present invention.

Although not shown, information for managing a group of programs stored in the storage medium, such as version information and a creator, is also stored, and information dependent on the OS or the like on the program reading side, such as a program, is stored. An icon or the like for identification display may also be stored.

Further, data dependent on various programs is also managed in the directory. Also, if the programs and data to be installed are compressed,
A program for decompressing may also be stored.

The functions shown in FIGS. 7 and 11 in this embodiment are executed by a program installed from the outside.
It may be performed by a host computer. And in that case, CD-ROM, flash memory, FD
The present invention can be applied to a case in which a group of information including a program is supplied to an output device from a storage medium such as the above or from an external storage medium via a network.

As described above, the storage medium storing the program codes of the software for realizing the functions of the above-described embodiments is supplied to the system or the apparatus, and the computer (or CPU or MP) of the system or the apparatus is supplied.
It goes without saying that the object of the present invention is also achieved when U) reads and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes a new function of the present invention, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, C
D-ROM, CD-R, DVD-ROM, magnetic tape,
A non-volatile memory card, ROM, EEPROM, silicon disk, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) And the like perform part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided on a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instructions of the program code, The CPU provided in the function expansion board or function expansion unit performs part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included.

Further, the present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading a storage medium storing a program represented by software for achieving the present invention into the system or the apparatus, the system or the apparatus can enjoy the effects of the present invention. .

Further, by reading and reading a program represented by software for achieving the present invention from a database on a network by a communication program, the system or apparatus can be
It is possible to enjoy the effects of the present invention.

[0143]

As described above, the first embodiment according to the present invention is described.
According to the inventions of 4, 11 and 13, the designation of whether the material type of the recording sheet medium fed by the feeding unit is an OHP sheet and the detection of the fed recording sheet medium are performed. If the determination detection processing for determining whether or not the material type of the recording sheet medium is an OHP sheet is different, the image forming operation is switched, and the recording sheet medium being fed has an image formed on the back side. At one time, it is determined that the material type determination of the recording sheet medium is not performed, and the recording is unconditionally fed without performing the material type determination of the recording sheet medium and switching of the image forming operation. Since the image formation is performed on the recording sheet medium, for example, it is determined that the recording sheet medium on which one side is already image-formed and re-fed is not an OHP sheet when the front side image is formed. In this case, the execution of the detection processing by the OHP detection sensor itself is prohibited, so that the interruption of image formation due to the erroneous detection of the OHP sensor can be prevented. Image formation can be performed.

According to the fifth aspect, there is provided the second designating means for designating that the back side of the recording sheet medium fed by the feeding unit has already been formed with an image, and the determining means comprises: When the second designating means designates that the back side of the recording sheet medium has already been subjected to image formation, the judgment means judges that the material type judgment of the recording sheet medium is not to be performed. In a case where the recording sheet medium having an image formed on one side such as a sheet feeder can be turned over as a recording sheet medium and the operator can set the sheet sheet again in the sheet feeding port, the operator has already formed the back side image. An interface is provided so that it is possible to designate that a certain recording sheet medium has been set, and an OHP is provided for the recording sheet medium fed when the designation is made.
The execution of the detection process itself by the sensor is prohibited and the OH
Interruption of image formation due to erroneous detection of the P sensor can be prevented, and image formation can be performed correctly according to the type of recording sheet medium.

According to the sixth to tenth, twelfth and twelfth aspects,
Specifying whether the material type of the recording sheet medium fed by the feeding unit is an OHP sheet, detecting the recording sheet medium fed by the feeding unit, and detecting the material type of the recording sheet medium Is different from the judgment result of the judgment detection process for judging whether or not the sheet is an OHP sheet, the image forming operation is switched. After determining that the switching of the material type determination method of the sheet medium is to be performed, and performing the detection determination method switching process and the detection determination process of the recording sheet medium, image formation is performed on the recording sheet medium. In the case where the operator can set the recording sheet medium on which one side of the image is formed as a recording sheet medium, such as a manual sheet feeder, by turning over the recording sheet medium and re-setting the sheet feeding port, An interface is provided so that the author can specify that the recording sheet medium on which the backside image has been formed is set, and an image is provided for the recording sheet medium fed when the designation is made. An OH method is used to determine whether or not an OHP sheet is only based on a margin width outside the image range on the back surface of the formed recording sheet medium.
By switching the P sheet detection determination method, it is possible to prevent interruption of the image forming operation due to erroneous detection of the OHP sensor, and to form an image correctly according to the type of the recording sheet medium.

Accordingly, an image forming apparatus capable of preventing interruption of image forming operation due to erroneous detection of the reflection type OHP sensor and capable of correctly forming an image according to the type of recording sheet medium is provided. There are effects such as being able to be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of an image forming apparatus according to a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control unit shown in FIG.

FIG. 3 is a block diagram illustrating a configuration of a digital image processing unit illustrated in FIG. 1;

FIG. 4 is a diagram showing a type of a recording sheet medium (OHP sheet or plain paper (OHP sheet) displayed on a liquid crystal display unit of the operation unit shown in FIG. 2;
FIG. 9 is a schematic diagram illustrating an example of a setting screen for a recording sheet medium other than an HP sheet)).

FIG. 5 is a diagram showing a configuration of the OHP sensor shown in FIG.

6 is a diagram illustrating an OHP sheet identification operation of the OHP sensor shown in FIG.

FIG. 7 is a flowchart illustrating an example of a first control processing procedure in the image forming apparatus of the present invention.

FIG. 8 is a schematic diagram showing an example of a warning message displayed on a liquid crystal display unit of the operation unit shown in FIG.

FIG. 9 is a block diagram illustrating a detailed configuration of a printer processing unit of the color printer unit illustrated in FIG.

10 is a schematic diagram showing an example of a screen for designating the second side of both sides of a recording sheet medium displayed on the liquid crystal display unit of the operation unit shown in FIG. 2;

FIG. 11 is a flowchart illustrating an example of a second control processing procedure in the image forming apparatus of the present invention.

FIG. 12 is a diagram illustrating a memory map of a storage medium that stores various data processing programs that can be read by the image forming apparatus according to the present invention.

[Explanation of symbols]

 312 Digital image processing unit 313 External I / F unit 317 to 320 Image forming unit 333 Transfer belt 336, 337 Conveying roller 339, 338, 354 Pickup roller 353 Printer control I / F 355 Registration roller 362 Double-sided path conveying roller 363 Double-sided path 364 Paper feed roller 367 OHP sensor 401 CPU 402 Operation unit 403 Memory

Claims (14)

[Claims] 1. An image forming apparatus in which an image forming section performs an image forming operation on a recording sheet medium fed by a feeding section, wherein a material type of the recording sheet medium fed by the feeding section is provided. First designation means for designating whether or not the recording sheet medium is an OHP sheet, and detecting whether or not the material type of the recording sheet medium is an OHP sheet by detecting the recording sheet medium fed by the feeding section. Determining means; switching means for switching the image forming operation when the material type specification of the recording sheet medium by the first specifying means is different from the material type determination result of the recording sheet medium by the determining means; Determination means for determining whether or not to perform the material type determination of the recording sheet medium, and determination that the determination means does not perform the material type determination of the recording sheet medium by the determination means. In the case it has been made,
Control for performing image formation on a recording sheet medium fed unconditionally without determining the material type of the recording sheet medium by the determination unit and switching the image forming operation by the switching unit. And an image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the switching unit interrupts the image forming operation when the material type specification of the recording sheet medium by the first specifying unit is different from the material type determination result of the recording sheet medium by the determining unit. The image forming apparatus according to claim 1, wherein: 3. The recording device according to claim 1, wherein the determination unit detects an amount of reflected light with respect to light emitted to the surface of the recording sheet medium fed by the feeding unit, and determines a material type of the recording sheet medium based on the detection result. A determination unit configured to determine whether the recording sheet medium fed by the feeding unit has an image formed on a back surface of the recording sheet medium. 3. The image forming apparatus according to claim 1, wherein a determination is made that the material type determination is not performed. 4. The feeding section is capable of reversing and conveying the recording sheet medium on which an image has been formed by the image forming section and re-feeding the recording sheet medium to the image forming section. It is determined that the recording sheet medium re-fed by the unit has an image formed on the back surface,
4. The image forming apparatus according to claim 3, wherein the determination unit determines that the material type determination of the recording sheet medium is not performed. 5. The printing apparatus according to claim 1, further comprising: a second designating unit for designating that the back side of the recording sheet medium fed by the feeding unit has already been formed with an image. 4. The apparatus according to claim 3, wherein when the back surface of the recording sheet medium is designated as having an image formed thereon by the means, it is determined that the material type determination of the recording sheet medium is not performed by the determining means. The image forming apparatus as described in the above. 6. An image forming apparatus in which an image forming unit performs an image forming operation on a recording sheet medium fed by a feeding unit, wherein a material type of the recording sheet medium fed by the feeding unit is provided. First designation means for designating whether or not the recording sheet medium is an OHP sheet, and detecting whether or not the material type of the recording sheet medium is an OHP sheet by detecting the recording sheet medium fed by the feeding section. Judging means; first switching means for switching the image forming operation when the material type designation of the recording sheet medium by the first designation means is different from the material type judgment result of the recording sheet medium by the judging means; A second switching unit that switches a detection determination method of the recording sheet medium by the determination unit; and a switching of a detection determination method of the recording sheet medium by the determination unit by the second switching unit. Determining means for determining whether or not to perform the switching of the recording sheet medium detection determining method of the determining means, the switching processing by the second switching means; An image forming apparatus comprising: a control unit configured to perform a detection determination process by a determination unit and then control to form an image on a recording sheet medium. 7. The image forming operation when the material type designation of the recording sheet medium by the first designating means differs from the material type judgment result of the recording sheet medium by the judging means. The image forming apparatus according to claim 6, wherein the step of interrupting is stopped. 8. The recording device according to claim 1, wherein the determining unit detects an amount of reflected light with respect to light emitted to the surface of the recording sheet medium fed by the feeding unit, and determines a material type of the recording sheet medium based on the detection result. A reflection-type detection type for performing the determination, wherein the determination unit determines the determination by the second switching unit when the recording sheet medium fed by the feeding unit has an image formed on the back surface. 8. The image forming apparatus according to claim 6, wherein a determination is made to switch the detection / determination method of the recording sheet medium of the means. 9. The printing apparatus according to claim 1, wherein when the recording sheet medium being fed is already image-formed on the back side, the second switching unit sets the detection sheet judging method of the recording sheet medium by the judging unit so that the image forming is completed. 9. The image forming apparatus according to claim 8, wherein the method is changed to a method of determining whether or not an OHP sheet is determined only by a margin width outside the image range on the back surface of a recording sheet medium. 10. The printing apparatus according to claim 1, further comprising a second designating unit for designating that the back side of the recording sheet medium fed by the feeding unit has already been formed with an image. When the back surface of the recording sheet medium is designated as having an image formed thereon by the means, it is determined that the second switching means is to switch the method of detecting and determining the recording sheet medium by the determining means. The image forming apparatus according to claim 8, wherein: 11. A control method for an image forming apparatus in which an image forming unit performs an image forming operation on a recording sheet medium fed by a feeding unit, wherein the recording sheet medium fed by the feeding unit is provided. A first specifying step of specifying whether or not the material type of the recording sheet medium is an OHP sheet; and detecting whether the material type of the recording sheet medium is an OHP sheet by detecting the recording sheet medium fed by the feeding unit. A determining step of determining the material type of the recording sheet medium in the first specifying step and a switching step of switching the image forming operation if the material type determination result of the recording sheet medium in the determining step is different; A judging step of judging whether or not to judge the material type of the recording sheet medium in the judging step; and judging the material type of the recording sheet medium in the judging step in the judging step If the determination of the stomach effect has been made,
Forming an image on a recording sheet medium fed unconditionally without determining the material type of the recording sheet medium in the determining step and switching the image forming operation in the switching step. A method for controlling an image forming apparatus, comprising: 12. A control method for an image forming apparatus in which an image forming unit performs an image forming operation on a recording sheet medium fed by a feeding unit, wherein the recording sheet medium fed by the feeding unit is provided. A first specifying step of specifying whether or not the material type of the recording sheet medium is an OHP sheet; and detecting whether the material type of the recording sheet medium is an OHP sheet by detecting the recording sheet medium fed by the feeding unit. Determining the material type of the recording sheet medium in the first specifying step, and the first switching to switch the image forming operation when the material type determination result of the recording sheet medium in the determining step is different. And a second switching step of switching the detection and determination method of the recording sheet medium in the determination step; and setting the switching of the detection and determination method of the recording sheet medium in the determination step by the second switching step. A determination step of determining whether or not to perform the switching; and a determination that the switching of the method of detecting and determining the recording sheet medium in the determination step is performed in the determination step. Performing a switching process and a detection determination process in the determination process, and then performing image formation on a recording sheet medium. A method for controlling an image forming apparatus, comprising: 13. An image forming apparatus in which an image forming unit performs an image forming operation on a recording sheet medium fed by a feeding unit, wherein a material type of the recording sheet medium fed by the feeding unit is provided. A first designating step of designating whether or not the sheet type is an OHP sheet; and detecting a recording sheet medium fed by the feeding section to determine whether or not the material type of the recording sheet medium is an OHP sheet. A determining step; a switching step of switching the image forming operation when the material type specification of the recording sheet medium in the first specifying step is different from the material type determination result of the recording sheet medium in the determining step; A determination step of determining whether or not to determine the material type of the recording sheet medium according to the above, and a determination that the determination of the material type of the recording sheet medium by the determination step is not performed in the determination step. If it is,
Performing the image formation on the recording sheet medium fed unconditionally without performing the determination of the material type of the recording sheet medium in the determination step and the image formation switching in the switching step. A storage medium storing the computer program readable by a computer. 14. A material type of the recording sheet medium fed by the feeding section to an image forming apparatus in which the image forming section performs an image forming operation on the recording sheet medium fed by the feeding section. A first designating step of designating whether or not the sheet type is an OHP sheet; and detecting a recording sheet medium fed by the feeding section to determine whether or not the material type of the recording sheet medium is an OHP sheet. A determining step; a first switching step of switching the image forming operation when the material type specification of the recording sheet medium in the first specifying step and the material type determination result of the recording sheet medium in the determining step are different; A second switching step of switching the detection and determination method of the recording sheet medium in the determination step, and whether to switch the detection and determination method of the recording sheet medium in the determination step in the second switching step A switching step by the second switching step and the determination step when the determination step determines that the switching of the detection method of the recording sheet medium in the determination step is to be performed in the determination step. Performing image formation on a recording sheet medium after performing a detection determination process by a computer, and a computer-readable storage medium storing a computer-readable program.